diff --git a/cmake/GoogleCloudCppCommon.cmake b/cmake/GoogleCloudCppCommon.cmake
index 32080fa16b380..0fe6e88199a43 100644
--- a/cmake/GoogleCloudCppCommon.cmake
+++ b/cmake/GoogleCloudCppCommon.cmake
@@ -81,11 +81,7 @@ elseif (GOOGLE_CLOUD_CPP_GENERATE_DOXYGEN)
         "GOOGLE_CLOUD_CPP_BIGTABLE_IAM_DEPRECATED(x)="
         "GOOGLE_CLOUD_CPP_SPANNER_ADMIN_API_DEPRECATED(x)="
         "GOOGLE_CLOUD_CPP_GENERATED_NS=v${PROJECT_VERSION_MAJOR}"
-        "GOOGLE_CLOUD_CPP_NS=v${PROJECT_VERSION_MAJOR}"
-        "GOOGLE_CLOUD_CPP_PUBSUB_NS=v${PROJECT_VERSION_MAJOR}"
-        "BIGTABLE_CLIENT_NS=v${PROJECT_VERSION_MAJOR}"
-        "SPANNER_CLIENT_NS=v${PROJECT_VERSION_MAJOR}"
-        "STORAGE_CLIENT_NS=v${PROJECT_VERSION_MAJOR}")
+        "GOOGLE_CLOUD_CPP_NS=v${PROJECT_VERSION_MAJOR}")
     set(DOXYGEN_HTML_TIMESTAMP YES)
     set(DOXYGEN_STRIP_FROM_INC_PATH "${PROJECT_SOURCE_DIR}")
     set(DOXYGEN_SHOW_USED_FILES NO)
diff --git a/google/cloud/bigtable/admin_client.cc b/google/cloud/bigtable/admin_client.cc
index 529d6f043dbfd..38eb9e6c9c023 100644
--- a/google/cloud/bigtable/admin_client.cc
+++ b/google/cloud/bigtable/admin_client.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace btadmin = ::google::bigtable::admin::v2;
 
@@ -429,7 +429,7 @@ std::shared_ptr<AdminClient> CreateDefaultAdminClient(std::string project,
                          internal::MakeOptions(std::move(options)));
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/admin_client.h b/google/cloud/bigtable/admin_client.h
index 0cc077c8148f4..e0130dd02fd69 100644
--- a/google/cloud/bigtable/admin_client.h
+++ b/google/cloud/bigtable/admin_client.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // Forward declare some classes so we can be friends.
 class TableAdmin;
 namespace internal {
@@ -306,7 +306,7 @@ std::shared_ptr<AdminClient> MakeAdminClient(std::string project,
 std::shared_ptr<AdminClient> CreateDefaultAdminClient(std::string project,
                                                       ClientOptions options);
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/admin_client_test.cc b/google/cloud/bigtable/admin_client_test.cc
index f9404458f3d03..82a00ae7bcf46 100644
--- a/google/cloud/bigtable/admin_client_test.cc
+++ b/google/cloud/bigtable/admin_client_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(AdminClientTest, Default) {
@@ -70,7 +70,7 @@ TEST(AdminClientTest, Logging) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/app_profile_config.cc b/google/cloud/bigtable/app_profile_config.cc
index cf8baacc27c65..7b93842483816 100644
--- a/google/cloud/bigtable/app_profile_config.cc
+++ b/google/cloud/bigtable/app_profile_config.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 AppProfileConfig AppProfileConfig::MultiClusterUseAny(std::string profile_id) {
   AppProfileConfig tmp;
   tmp.proto_.set_app_profile_id(std::move(profile_id));
@@ -56,7 +56,7 @@ void AppProfileUpdateConfig::RemoveIfPresent(std::string const& field_name) {
   paths.erase(i);
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/app_profile_config.h b/google/cloud/bigtable/app_profile_config.h
index 3c78a1f3eccfe..e9bf503e36c5a 100644
--- a/google/cloud/bigtable/app_profile_config.h
+++ b/google/cloud/bigtable/app_profile_config.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// Specify the initial configuration for an application profile.
 class AppProfileConfig {
  public:
@@ -119,7 +119,7 @@ class AppProfileUpdateConfig {
   google::bigtable::admin::v2::UpdateAppProfileRequest proto_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/app_profile_config_test.cc b/google/cloud/bigtable/app_profile_config_test.cc
index 4964c34b26b65..e5e1bdd374f57 100644
--- a/google/cloud/bigtable/app_profile_config_test.cc
+++ b/google/cloud/bigtable/app_profile_config_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 TEST(AppProfileConfig, MultiClusterUseAny) {
   auto proto = AppProfileConfig::MultiClusterUseAny("my-profile").as_proto();
@@ -128,7 +128,7 @@ TEST(AppProfileUpdateConfig, SetSeveral) {
   EXPECT_TRUE(HasFieldNameOnce(proto.update_mask(), "single_cluster_routing"));
 }
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/async_read_stream_test.cc b/google/cloud/bigtable/async_read_stream_test.cc
index a9c6a795a3699..f9d3536e30d8c 100644
--- a/google/cloud/bigtable/async_read_stream_test.cc
+++ b/google/cloud/bigtable/async_read_stream_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -717,7 +717,7 @@ TEST_F(AsyncReadStreamTest, DiscardAfterReturningFalse) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/async_row_reader.h b/google/cloud/bigtable/async_row_reader.h
index 558ec444dbd94..9e100fd8068f1 100644
--- a/google/cloud/bigtable/async_row_reader.h
+++ b/google/cloud/bigtable/async_row_reader.h
@@ -39,7 +39,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Objects of this class represent the state of reading rows via AsyncReadRows.
  *
@@ -424,7 +424,7 @@ class AsyncRowReader : public std::enable_shared_from_this<
   int recursion_level_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/async_row_reader_test.cc b/google/cloud/bigtable/async_row_reader_test.cc
index 331a7c680a863..123c3f7cb597c 100644
--- a/google/cloud/bigtable/async_row_reader_test.cc
+++ b/google/cloud/bigtable/async_row_reader_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -1075,7 +1075,7 @@ TEST_F(TableAsyncReadRowsTest, ReadRowError) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/bigtable_version_test.cc b/google/cloud/bigtable/bigtable_version_test.cc
index d01131eee7405..e98044e34956b 100644
--- a/google/cloud/bigtable/bigtable_version_test.cc
+++ b/google/cloud/bigtable/bigtable_version_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 using ::testing::HasSubstr;
 using ::testing::Not;
 using ::testing::StartsWith;
@@ -50,7 +50,7 @@ TEST(StorageVersionTest, HasMetadataWhenDefined) {
   EXPECT_THAT(version_string(), Not(HasSubstr("+")));
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/cell.h b/google/cloud/bigtable/cell.h
index f4f205373f43b..aa50a3f4d0220 100644
--- a/google/cloud/bigtable/cell.h
+++ b/google/cloud/bigtable/cell.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class Cell;
 struct Mutation;
 Mutation SetCell(Cell);
@@ -177,7 +177,7 @@ class Cell {
   friend Mutation SetCell(Cell);
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/cell_test.cc b/google/cloud/bigtable/cell_test.cc
index 3d79fabdc6cf4..f9b5686e13579 100644
--- a/google/cloud/bigtable/cell_test.cc
+++ b/google/cloud/bigtable/cell_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 /// @test Verify Cell instantiation and trivial accessors.
@@ -95,7 +95,7 @@ TEST(CellTest, RValueRefAccessors) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/client_options.cc b/google/cloud/bigtable/client_options.cc
index 3af3bc8c4c43f..2170da0c8759f 100644
--- a/google/cloud/bigtable/client_options.cc
+++ b/google/cloud/bigtable/client_options.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 Options&& MakeOptions(ClientOptions&& o) {
   if (!o.connection_pool_name_.empty()) {
@@ -71,7 +71,7 @@ BackgroundThreadsFactory ClientOptions::background_threads_factory() const {
   return google::cloud::internal::MakeBackgroundThreadsFactory(opts_);
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/client_options.h b/google/cloud/bigtable/client_options.h
index f2a65b9478263..f077fd5f7b685 100644
--- a/google/cloud/bigtable/client_options.h
+++ b/google/cloud/bigtable/client_options.h
@@ -35,7 +35,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class ClientOptions;
 namespace internal {
 Options&& MakeOptions(ClientOptions&& o);
@@ -476,7 +476,7 @@ class ClientOptions {
   Options opts_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/client_options_test.cc b/google/cloud/bigtable/client_options_test.cc
index 3e8725afd41b6..850871dfe612b 100644
--- a/google/cloud/bigtable/client_options_test.cc
+++ b/google/cloud/bigtable/client_options_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct ClientOptionsTestTraits {
   static std::string const& InstanceAdminEndpoint(
       ClientOptions const& options) {
@@ -585,7 +585,7 @@ TEST(ClientOptionsTest, CustomBackgroundThreads) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/cluster_config.cc b/google/cloud/bigtable/cluster_config.cc
index 880026edec9bb..d60f7b83c0f66 100644
--- a/google/cloud/bigtable/cluster_config.cc
+++ b/google/cloud/bigtable/cluster_config.cc
@@ -16,7 +16,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // The names for these constants are taken from the proto, and follow the
 // conventions from proto files.
 
@@ -27,7 +27,7 @@ constexpr ClusterConfig::StorageType ClusterConfig::SSD;
 // NOLINTNEXTLINE(readability-identifier-naming)
 constexpr ClusterConfig::StorageType ClusterConfig::HDD;
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/cluster_config.h b/google/cloud/bigtable/cluster_config.h
index e74069e69f476..eee5d392a5b4d 100644
--- a/google/cloud/bigtable/cluster_config.h
+++ b/google/cloud/bigtable/cluster_config.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Specify the initial configuration for a new cluster.
 class ClusterConfig {
@@ -71,7 +71,7 @@ class ClusterConfig {
   google::bigtable::admin::v2::Cluster proto_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/cluster_config_test.cc b/google/cloud/bigtable/cluster_config_test.cc
index b1434ad7c0e3c..b4132435b221f 100644
--- a/google/cloud/bigtable/cluster_config_test.cc
+++ b/google/cloud/bigtable/cluster_config_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -65,7 +65,7 @@ TEST(ClusterConfigTest, SetEncryptionConfig) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/cluster_list_responses.h b/google/cloud/bigtable/cluster_list_responses.h
index 1e986ef1430b7..2e6695cc9aec5 100644
--- a/google/cloud/bigtable/cluster_list_responses.h
+++ b/google/cloud/bigtable/cluster_list_responses.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * The response for an asynchronous request listing all the clusters.
  */
@@ -42,7 +42,7 @@ struct ClusterList {
   std::vector<std::string> failed_locations;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/column_family.h b/google/cloud/bigtable/column_family.h
index 0ff67b26f3655..3733cc09ee855 100644
--- a/google/cloud/bigtable/column_family.h
+++ b/google/cloud/bigtable/column_family.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Implement a thin wrapper around google::bigtable::admin::v2::GcRule.
  *
@@ -220,7 +220,7 @@ class ColumnFamilyModification {
   ::google::bigtable::admin::v2::ModifyColumnFamiliesRequest::Modification mod_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/column_family_test.cc b/google/cloud/bigtable/column_family_test.cc
index b8772023014af..8729c0714c4d9 100644
--- a/google/cloud/bigtable/column_family_test.cc
+++ b/google/cloud/bigtable/column_family_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _h;
@@ -147,7 +147,7 @@ TEST(ColumnFamilyModification, Drop) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/completion_queue.h b/google/cloud/bigtable/completion_queue.h
index 3819ea72e6ce0..3bb241e366114 100644
--- a/google/cloud/bigtable/completion_queue.h
+++ b/google/cloud/bigtable/completion_queue.h
@@ -21,10 +21,10 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 using ::google::cloud::CompletionQueue;
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/data_client.cc b/google/cloud/bigtable/data_client.cc
index 143fd174d69e9..0f4cdc6cbaed8 100644
--- a/google/cloud/bigtable/data_client.cc
+++ b/google/cloud/bigtable/data_client.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace btproto = ::google::bigtable::v2;
 
@@ -207,7 +207,7 @@ std::shared_ptr<DataClient> CreateDefaultDataClient(std::string project_id,
                         internal::MakeOptions(std::move(options)));
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/data_client.h b/google/cloud/bigtable/data_client.h
index 621187b179565..079d0038e608d 100644
--- a/google/cloud/bigtable/data_client.h
+++ b/google/cloud/bigtable/data_client.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // Forward declare some classes so we can be friends.
 class Table;
 namespace internal {
@@ -200,7 +200,7 @@ inline std::string InstanceName(std::shared_ptr<DataClient> const& client) {
          client->instance_id();
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/data_client_test.cc b/google/cloud/bigtable/data_client_test.cc
index d6a5a482e13f6..b523f8e95509d 100644
--- a/google/cloud/bigtable/data_client_test.cc
+++ b/google/cloud/bigtable/data_client_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(DataClientTest, Default) {
@@ -73,7 +73,7 @@ TEST(DataClientTest, Logging) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/expr.cc b/google/cloud/bigtable/expr.cc
index f3e7b76cceb3f..6f239f10d10a4 100644
--- a/google/cloud/bigtable/expr.cc
+++ b/google/cloud/bigtable/expr.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 google::type::Expr Expression(std::string expression, std::string title,
                               std::string description, std::string location) {
   google::type::Expr expr;
@@ -43,7 +43,7 @@ std::ostream& operator<<(std::ostream& stream, google::type::Expr const& e) {
   return stream;
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/expr.h b/google/cloud/bigtable/expr.h
index af00db8ddd0ae..4df2bcc0d2a77 100644
--- a/google/cloud/bigtable/expr.h
+++ b/google/cloud/bigtable/expr.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Create a google::type::Expr.
  *
@@ -44,7 +44,7 @@ google::type::Expr Expression(std::string expression, std::string title = "",
 
 std::ostream& operator<<(std::ostream& stream, google::type::Expr const&);
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/expr_test.cc b/google/cloud/bigtable/expr_test.cc
index dabba8ba1ff8d..a136fc79102dc 100644
--- a/google/cloud/bigtable/expr_test.cc
+++ b/google/cloud/bigtable/expr_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(ExprTest, Trivial) {
@@ -65,7 +65,7 @@ TEST(ExprTest, Printing) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/filters.h b/google/cloud/bigtable/filters.h
index 30d803c7545bf..d6741aae1a4e4 100644
--- a/google/cloud/bigtable/filters.h
+++ b/google/cloud/bigtable/filters.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define the interfaces to create filter expressions.
  *
@@ -695,7 +695,7 @@ class Filter {
   google::bigtable::v2::RowFilter filter_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/filters_test.cc b/google/cloud/bigtable/filters_test.cc
index 6950f4698be4a..32103a7b6b914 100644
--- a/google/cloud/bigtable/filters_test.cc
+++ b/google/cloud/bigtable/filters_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -410,7 +410,7 @@ TEST(FiltersTest, RowFilterCtor) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/iam_binding.cc b/google/cloud/bigtable/iam_binding.cc
index 107a6175c9d8b..a76a547d62602 100644
--- a/google/cloud/bigtable/iam_binding.cc
+++ b/google/cloud/bigtable/iam_binding.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 google::iam::v1::Binding IamBinding(
     std::string role, std::initializer_list<std::string> members) {
   return IamBinding(std::move(role), members.begin(), members.end());
@@ -73,7 +73,7 @@ std::ostream& operator<<(std::ostream& os,
   return os;
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/iam_binding.h b/google/cloud/bigtable/iam_binding.h
index 5e159d7a4e331..aa1be27850f96 100644
--- a/google/cloud/bigtable/iam_binding.h
+++ b/google/cloud/bigtable/iam_binding.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Create a google::iam::v1::Binding.
  *
@@ -171,7 +171,7 @@ google::iam::v1::Binding IamBinding(std::string role, InputIt begin,
                                 std::move(condition));
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/iam_binding_test.cc b/google/cloud/bigtable/iam_binding_test.cc
index 8f7dedbbde5bf..08aa11f53693c 100644
--- a/google/cloud/bigtable/iam_binding_test.cc
+++ b/google/cloud/bigtable/iam_binding_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(IamBinding, IterCtor) {
@@ -96,7 +96,7 @@ TEST(IamBinding, PrintingWithCondition) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/iam_policy.cc b/google/cloud/bigtable/iam_policy.cc
index 34c5719bfac1b..1c05628ec773f 100644
--- a/google/cloud/bigtable/iam_policy.cc
+++ b/google/cloud/bigtable/iam_policy.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 google::iam::v1::Policy IamPolicy(
     std::initializer_list<google::iam::v1::Binding> bindings, std::string etag,
     std::int32_t version) {
@@ -59,7 +59,7 @@ void RemoveBindingFromPolicy(
       });
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/iam_policy.h b/google/cloud/bigtable/iam_policy.h
index 9423fb3ea81a3..1c0029216db7b 100644
--- a/google/cloud/bigtable/iam_policy.h
+++ b/google/cloud/bigtable/iam_policy.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 template <class InputIt>
 /**
  * Create a google::iam::v1::Policy.
@@ -140,7 +140,7 @@ void RemoveBindingFromPolicy(
     google::protobuf::RepeatedPtrField<google::iam::v1::Binding>::iterator
         to_remove);
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/iam_policy_test.cc b/google/cloud/bigtable/iam_policy_test.cc
index cde9b61a77f37..c2460c2699205 100644
--- a/google/cloud/bigtable/iam_policy_test.cc
+++ b/google/cloud/bigtable/iam_policy_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 template <typename Iter>
@@ -84,7 +84,7 @@ TEST(IamPolicy, Printing) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/idempotent_mutation_policy.cc b/google/cloud/bigtable/idempotent_mutation_policy.cc
index 628c095f71517..72814b64b9507 100644
--- a/google/cloud/bigtable/idempotent_mutation_policy.cc
+++ b/google/cloud/bigtable/idempotent_mutation_policy.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::unique_ptr<IdempotentMutationPolicy> DefaultIdempotentMutationPolicy() {
   return std::unique_ptr<IdempotentMutationPolicy>(
       new SafeIdempotentMutationPolicy);
@@ -59,7 +59,7 @@ bool AlwaysRetryMutationPolicy::is_idempotent(
   return true;
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/idempotent_mutation_policy.h b/google/cloud/bigtable/idempotent_mutation_policy.h
index f9264bfd3f544..c3c60fc390e66 100644
--- a/google/cloud/bigtable/idempotent_mutation_policy.h
+++ b/google/cloud/bigtable/idempotent_mutation_policy.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Defines the interface to control which mutations are idempotent and therefore
@@ -82,7 +82,7 @@ class AlwaysRetryMutationPolicy : public IdempotentMutationPolicy {
       google::bigtable::v2::CheckAndMutateRowRequest const&) override;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/idempotent_mutation_policy_test.cc b/google/cloud/bigtable/idempotent_mutation_policy_test.cc
index 2706b6fe70338..4ad54c6223cd6 100644
--- a/google/cloud/bigtable/idempotent_mutation_policy_test.cc
+++ b/google/cloud/bigtable/idempotent_mutation_policy_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _ms;
@@ -52,7 +52,7 @@ TEST(IdempotentMutationPolicyTest, AlwaysRetry) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_admin.cc b/google/cloud/bigtable/instance_admin.cc
index 966d91607f8a5..9d0ad7cb4dde5 100644
--- a/google/cloud/bigtable/instance_admin.cc
+++ b/google/cloud/bigtable/instance_admin.cc
@@ -33,7 +33,7 @@ namespace btadmin = ::google::bigtable::admin::v2;
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 static_assert(std::is_copy_assignable<bigtable::InstanceAdmin>::value,
               "bigtable::InstanceAdmin must be CopyAssignable");
 
@@ -644,7 +644,7 @@ StatusOr<google::cloud::IamPolicy> InstanceAdmin::ProtoToWrapper(
   return result;
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_admin.h b/google/cloud/bigtable/instance_admin.h
index 569712484d638..b0cad7e4ecea4 100644
--- a/google/cloud/bigtable/instance_admin.h
+++ b/google/cloud/bigtable/instance_admin.h
@@ -38,7 +38,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Implements the APIs to administer Cloud Bigtable instances.
  *
@@ -779,7 +779,7 @@ class InstanceAdmin {
   std::shared_ptr<BackgroundThreads> background_threads_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_admin_client.cc b/google/cloud/bigtable/instance_admin_client.cc
index e10b086057033..8788bd409eeeb 100644
--- a/google/cloud/bigtable/instance_admin_client.cc
+++ b/google/cloud/bigtable/instance_admin_client.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btadmin = ::google::bigtable::admin::v2;
@@ -363,7 +363,7 @@ std::shared_ptr<InstanceAdminClient> CreateDefaultInstanceAdminClient(
                                  internal::MakeOptions(std::move(options)));
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_admin_client.h b/google/cloud/bigtable/instance_admin_client.h
index 5391266e08595..8b8f210bf8dcd 100644
--- a/google/cloud/bigtable/instance_admin_client.h
+++ b/google/cloud/bigtable/instance_admin_client.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // Forward declare some classes so we can be friends.
 class InstanceAdmin;
 namespace internal {
@@ -340,7 +340,7 @@ std::shared_ptr<InstanceAdminClient> MakeInstanceAdminClient(
 std::shared_ptr<InstanceAdminClient> CreateDefaultInstanceAdminClient(
     std::string project, ClientOptions options);
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_admin_client_test.cc b/google/cloud/bigtable/instance_admin_client_test.cc
index 4896ca5144f30..dd01416fbe329 100644
--- a/google/cloud/bigtable/instance_admin_client_test.cc
+++ b/google/cloud/bigtable/instance_admin_client_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(InstanceAdminClientTest, Default) {
@@ -70,7 +70,7 @@ TEST(InstanceAdminClientTest, Logging) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_admin_test.cc b/google/cloud/bigtable/instance_admin_test.cc
index 84cc802cbc157..1d6ad77c18eab 100644
--- a/google/cloud/bigtable/instance_admin_test.cc
+++ b/google/cloud/bigtable/instance_admin_test.cc
@@ -32,7 +32,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btadmin = ::google::bigtable::admin::v2;
@@ -1038,7 +1038,7 @@ TEST_F(InstanceAdminTest, GetInstance) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_config.cc b/google/cloud/bigtable/instance_config.cc
index 56baf48665c86..b403196fef0cf 100644
--- a/google/cloud/bigtable/instance_config.cc
+++ b/google/cloud/bigtable/instance_config.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // The names for these constants are taken from the proto, and follow the
 // conventions from proto files.
 
@@ -28,7 +28,7 @@ constexpr InstanceConfig::InstanceType InstanceConfig::PRODUCTION;
 // NOLINTNEXTLINE(readability-identifier-naming)
 constexpr InstanceConfig::InstanceType InstanceConfig::DEVELOPMENT;
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_config.h b/google/cloud/bigtable/instance_config.h
index 4ec95bb56a94e..213fb54fa7258 100644
--- a/google/cloud/bigtable/instance_config.h
+++ b/google/cloud/bigtable/instance_config.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// Specify the initial configuration for a new instance.
 class InstanceConfig {
  public:
@@ -81,7 +81,7 @@ class InstanceConfig {
   google::bigtable::admin::v2::CreateInstanceRequest proto_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_config_test.cc b/google/cloud/bigtable/instance_config_test.cc
index 03b5126cdfd2d..c2d61309793f3 100644
--- a/google/cloud/bigtable/instance_config_test.cc
+++ b/google/cloud/bigtable/instance_config_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(InstanceConfigTest, Constructor) {
@@ -76,7 +76,7 @@ TEST(InstanceConfigTest, SetLabels) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_list_responses.h b/google/cloud/bigtable/instance_list_responses.h
index 86f5da98e19d7..4b6f255be4e5d 100644
--- a/google/cloud/bigtable/instance_list_responses.h
+++ b/google/cloud/bigtable/instance_list_responses.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * The response for an asynchronous request listing all the instances.
  */
@@ -42,7 +42,7 @@ struct InstanceList {
   std::vector<std::string> failed_locations;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_update_config.cc b/google/cloud/bigtable/instance_update_config.cc
index 0c048ef61801a..44462bcf0ca41 100644
--- a/google/cloud/bigtable/instance_update_config.cc
+++ b/google/cloud/bigtable/instance_update_config.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // The names for these constants are taken from the proto, and follow the
 // conventions from proto files.
 
@@ -37,7 +37,7 @@ constexpr InstanceUpdateConfig::StateType InstanceUpdateConfig::READY;
 // NOLINTNEXTLINE(readability-identifier-naming)
 constexpr InstanceUpdateConfig::StateType InstanceUpdateConfig::CREATING;
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_update_config.h b/google/cloud/bigtable/instance_update_config.h
index 859d9100cad9c..7d6981466d102 100644
--- a/google/cloud/bigtable/instance_update_config.h
+++ b/google/cloud/bigtable/instance_update_config.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 using Instance = ::google::bigtable::admin::v2::Instance;
 
 /// Specify the initial configuration for updating an instance.
@@ -127,7 +127,7 @@ class InstanceUpdateConfig {
   google::bigtable::admin::v2::PartialUpdateInstanceRequest proto_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/instance_update_config_test.cc b/google/cloud/bigtable/instance_update_config_test.cc
index 6f9bf7e9004bc..a6cdbb63a4c7a 100644
--- a/google/cloud/bigtable/instance_update_config_test.cc
+++ b/google/cloud/bigtable/instance_update_config_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btadmin = ::google::bigtable::admin::v2;
@@ -110,7 +110,7 @@ TEST(InstanceUpdateConfigTest, SetLabels) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_bulk_apply.cc b/google/cloud/bigtable/internal/async_bulk_apply.cc
index cef984c73ffd5..2849c0733c09e 100644
--- a/google/cloud/bigtable/internal/async_bulk_apply.cc
+++ b/google/cloud/bigtable/internal/async_bulk_apply.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 future<std::vector<FailedMutation>> AsyncRetryBulkApply::Create(
@@ -105,7 +105,7 @@ void AsyncRetryBulkApply::SetPromise() {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_bulk_apply.h b/google/cloud/bigtable/internal/async_bulk_apply.h
index 36d99c7489b8f..5c70eecd34182 100644
--- a/google/cloud/bigtable/internal/async_bulk_apply.h
+++ b/google/cloud/bigtable/internal/async_bulk_apply.h
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Implement the retry loop for AsyncBulkApply.
@@ -74,7 +74,7 @@ class AsyncRetryBulkApply
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_bulk_apply_test.cc b/google/cloud/bigtable/internal/async_bulk_apply_test.cc
index bba7b8aee12d4..ec959420fad7b 100644
--- a/google/cloud/bigtable/internal/async_bulk_apply_test.cc
+++ b/google/cloud/bigtable/internal/async_bulk_apply_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -466,7 +466,7 @@ TEST_F(AsyncBulkApplyTest, CancelDuringBackoff) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_longrunning_op.h b/google/cloud/bigtable/internal/async_longrunning_op.h
index fa07c4066a008..a63798e5c2ff4 100644
--- a/google/cloud/bigtable/internal/async_longrunning_op.h
+++ b/google/cloud/bigtable/internal/async_longrunning_op.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -153,7 +153,7 @@ future<StatusOr<Response>> StartAsyncLongrunningOp(
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_longrunning_op_test.cc b/google/cloud/bigtable/internal/async_longrunning_op_test.cc
index 9da2de7f8b282..32b05aa06b23e 100644
--- a/google/cloud/bigtable/internal/async_longrunning_op_test.cc
+++ b/google/cloud/bigtable/internal/async_longrunning_op_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _ms;
@@ -266,7 +266,7 @@ TEST_F(AsyncLongrunningOperationTest, ImmediateSuccess) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_poll_op.h b/google/cloud/bigtable/internal/async_poll_op.h
index 3336459f0ff67..1f79df82a4570 100644
--- a/google/cloud/bigtable/internal/async_poll_op.h
+++ b/google/cloud/bigtable/internal/async_poll_op.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /// SFINAE matcher for `future<StatusOr<absl::optional<T>>>`, false branch.
@@ -218,7 +218,7 @@ StartAsyncPollOp(char const* location,
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_poll_op_test.cc b/google/cloud/bigtable/internal/async_poll_op_test.cc
index 36d7241aefcae..62b55c51b2a02 100644
--- a/google/cloud/bigtable/internal/async_poll_op_test.cc
+++ b/google/cloud/bigtable/internal/async_poll_op_test.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _ms;
@@ -189,7 +189,7 @@ TEST_F(AsyncPollOpTest, AsyncPollOpTestPolicyExhausted) {
   EXPECT_EQ(StatusCode::kUnknown, res.status().code());
 }
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_retry_multi_page.h b/google/cloud/bigtable/internal/async_retry_multi_page.h
index 8e33e60e5eec0..103fdd418c7df 100644
--- a/google/cloud/bigtable/internal/async_retry_multi_page.h
+++ b/google/cloud/bigtable/internal/async_retry_multi_page.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 template <typename AsyncCallType, typename Request, typename Accumulator,
@@ -224,7 +224,7 @@ future<StatusOr<Accumulator>> StartAsyncRetryMultiPage(
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_retry_multi_page_test.cc b/google/cloud/bigtable/internal/async_retry_multi_page_test.cc
index aca78d1636cf1..11a57b072cda6 100644
--- a/google/cloud/bigtable/internal/async_retry_multi_page_test.cc
+++ b/google/cloud/bigtable/internal/async_retry_multi_page_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _ms;
@@ -351,7 +351,7 @@ TEST_F(AsyncMultipageFutureTest, PermanentErrorsAreNotRetried) {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_retry_op.h b/google/cloud/bigtable/internal/async_retry_op.h
index f10e741b5b752..8f44dec3d4511 100644
--- a/google/cloud/bigtable/internal/async_retry_op.h
+++ b/google/cloud/bigtable/internal/async_retry_op.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -57,7 +57,7 @@ class ConstantIdempotencyPolicy {
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_retry_unary_rpc_and_poll.h b/google/cloud/bigtable/internal/async_retry_unary_rpc_and_poll.h
index 2382113b44fa1..eb9bc77e35085 100644
--- a/google/cloud/bigtable/internal/async_retry_unary_rpc_and_poll.h
+++ b/google/cloud/bigtable/internal/async_retry_unary_rpc_and_poll.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -113,7 +113,7 @@ future<StatusOr<Response>> AsyncStartPollAfterRetryUnaryRpc(
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_retry_unary_rpc_and_poll_test.cc b/google/cloud/bigtable/internal/async_retry_unary_rpc_and_poll_test.cc
index 2b08c0f3a752b..36cf6dea970d0 100644
--- a/google/cloud/bigtable/internal/async_retry_unary_rpc_and_poll_test.cc
+++ b/google/cloud/bigtable/internal/async_retry_unary_rpc_and_poll_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -259,7 +259,7 @@ TEST_F(AsyncStartPollAfterRetryUnaryRpcTest, FinalErrorIsPassedOn) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_row_sampler.cc b/google/cloud/bigtable/internal/async_row_sampler.cc
index 236f5bebfa5b2..8bdf1b50cc6ac 100644
--- a/google/cloud/bigtable/internal/async_row_sampler.cc
+++ b/google/cloud/bigtable/internal/async_row_sampler.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace btproto = ::google::bigtable::v2;
@@ -118,7 +118,7 @@ void AsyncRowSampler::OnFinish(Status const& status) {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_row_sampler.h b/google/cloud/bigtable/internal/async_row_sampler.h
index 2cff8cf18f57e..3ef216fef3051 100644
--- a/google/cloud/bigtable/internal/async_row_sampler.h
+++ b/google/cloud/bigtable/internal/async_row_sampler.h
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Objects of this class represent the state of receiving row keys via
@@ -73,7 +73,7 @@ class AsyncRowSampler : public std::enable_shared_from_this<AsyncRowSampler> {
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/async_row_sampler_test.cc b/google/cloud/bigtable/internal/async_row_sampler_test.cc
index 8cc0a85979393..ed816cbb71c23 100644
--- a/google/cloud/bigtable/internal/async_row_sampler_test.cc
+++ b/google/cloud/bigtable/internal/async_row_sampler_test.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -448,7 +448,7 @@ TEST_F(AsyncSampleRowKeysTest, CancelMidStream) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/bulk_mutator.cc b/google/cloud/bigtable/internal/bulk_mutator.cc
index 02415569fdc62..5289469d2234b 100644
--- a/google/cloud/bigtable/internal/bulk_mutator.cc
+++ b/google/cloud/bigtable/internal/bulk_mutator.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace btproto = ::google::bigtable::v2;
@@ -216,7 +216,7 @@ std::vector<FailedMutation> BulkMutator::OnRetryDone() && {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/bulk_mutator.h b/google/cloud/bigtable/internal/bulk_mutator.h
index b184fd32c2adf..841f6cb8aea29 100644
--- a/google/cloud/bigtable/internal/bulk_mutator.h
+++ b/google/cloud/bigtable/internal/bulk_mutator.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 class BulkMutatorState {
  public:
@@ -134,7 +134,7 @@ class BulkMutator {
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/bulk_mutator_test.cc b/google/cloud/bigtable/internal/bulk_mutator_test.cc
index 7a94874295642..8ea0126e0680d 100644
--- a/google/cloud/bigtable/internal/bulk_mutator_test.cc
+++ b/google/cloud/bigtable/internal/bulk_mutator_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -482,7 +482,7 @@ TEST(MultipleRowsMutatorTest, UnconfirmedAreFailed) {
 }
 
 }  // anonymous namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/common_client.cc b/google/cloud/bigtable/internal/common_client.cc
index 8ebf710c30486..997b4f4a657df 100644
--- a/google/cloud/bigtable/internal/common_client.cc
+++ b/google/cloud/bigtable/internal/common_client.cc
@@ -16,7 +16,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 ConnectionRefreshState::ConnectionRefreshState(
@@ -126,7 +126,7 @@ void OutstandingTimers::CancelAll() {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/common_client.h b/google/cloud/bigtable/internal/common_client.h
index 9641ba650355a..48102a5f1b651 100644
--- a/google/cloud/bigtable/internal/common_client.h
+++ b/google/cloud/bigtable/internal/common_client.h
@@ -32,7 +32,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -260,7 +260,7 @@ class CommonClient {
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/common_client_test.cc b/google/cloud/bigtable/internal/common_client_test.cc
index 9c9df6f877789..0363dfe7d5df2 100644
--- a/google/cloud/bigtable/internal/common_client_test.cc
+++ b/google/cloud/bigtable/internal/common_client_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 using TimerFuture = future<StatusOr<std::chrono::system_clock::time_point>>;
@@ -108,7 +108,7 @@ TEST_F(OutstandingTimersTest, TimerRegisteredAfterCancelAllGetCancelled) {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/defaults.cc b/google/cloud/bigtable/internal/defaults.cc
index 2b695ec6f5210..25704856fdf72 100644
--- a/google/cloud/bigtable/internal/defaults.cc
+++ b/google/cloud/bigtable/internal/defaults.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace {
@@ -157,7 +157,7 @@ Options DefaultOptions(Options opts) {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/defaults.h b/google/cloud/bigtable/internal/defaults.h
index baadbcca4f23d..08a2f3b392c9c 100644
--- a/google/cloud/bigtable/internal/defaults.h
+++ b/google/cloud/bigtable/internal/defaults.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 int DefaultConnectionPoolSize();
@@ -42,7 +42,7 @@ int DefaultConnectionPoolSize();
 Options DefaultOptions(Options opts = {});
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/defaults_test.cc b/google/cloud/bigtable/internal/defaults_test.cc
index 73e217433632f..038e80fc3b8ac 100644
--- a/google/cloud/bigtable/internal/defaults_test.cc
+++ b/google/cloud/bigtable/internal/defaults_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -248,7 +248,7 @@ TEST(ConnectionRefreshRange, BothSetInvalidUsesMax) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/google_bytes_traits.cc b/google/cloud/bigtable/internal/google_bytes_traits.cc
index 555ef7834219f..ca127084b8aa2 100644
--- a/google/cloud/bigtable/internal/google_bytes_traits.cc
+++ b/google/cloud/bigtable/internal/google_bytes_traits.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 bool ConsecutiveRowKeys(std::string const& a, std::string const& b) {
@@ -32,7 +32,7 @@ bool ConsecutiveRowKeys(std::string const& a, std::string const& b) {
   return b.compare(0, a.length(), a) == 0;
 }
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/google_bytes_traits.h b/google/cloud/bigtable/internal/google_bytes_traits.h
index 99defa9b9baf4..f6e93c38ad501 100644
--- a/google/cloud/bigtable/internal/google_bytes_traits.h
+++ b/google/cloud/bigtable/internal/google_bytes_traits.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 //@{
 /**
@@ -84,7 +84,7 @@ inline void ReserveCellValue(std::string& value, std::size_t reserve) {
 //@}
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/google_bytes_traits_test.cc b/google/cloud/bigtable/internal/google_bytes_traits_test.cc
index 4813527d2237e..fb9a839437cff 100644
--- a/google/cloud/bigtable/internal/google_bytes_traits_test.cc
+++ b/google/cloud/bigtable/internal/google_bytes_traits_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -32,7 +32,7 @@ TEST(GoogleBytesTraitsTest, ConsecutiveRowKeys) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_admin_client.cc b/google/cloud/bigtable/internal/logging_admin_client.cc
index 373905f6ad2e7..9e42708e3b224 100644
--- a/google/cloud/bigtable/internal/logging_admin_client.cc
+++ b/google/cloud/bigtable/internal/logging_admin_client.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace btadmin = ::google::bigtable::admin::v2;
@@ -417,7 +417,7 @@ LoggingAdminClient::AsyncGetOperation(
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_admin_client.h b/google/cloud/bigtable/internal/logging_admin_client.h
index baddebd029beb..c661947aa6c8c 100644
--- a/google/cloud/bigtable/internal/logging_admin_client.h
+++ b/google/cloud/bigtable/internal/logging_admin_client.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace btadmin = ::google::bigtable::admin::v2;
@@ -263,7 +263,7 @@ class LoggingAdminClient : public google::cloud::bigtable::AdminClient {
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_admin_client_test.cc b/google/cloud/bigtable/internal/logging_admin_client_test.cc
index 6920fb0b18ab7..5079ae54426f1 100644
--- a/google/cloud/bigtable/internal/logging_admin_client_test.cc
+++ b/google/cloud/bigtable/internal/logging_admin_client_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -365,7 +365,7 @@ TEST_F(LoggingAdminClientTest, TestIamPermissions) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_data_client.cc b/google/cloud/bigtable/internal/logging_data_client.cc
index 89693f6da1536..0d8714f89e823 100644
--- a/google/cloud/bigtable/internal/logging_data_client.cc
+++ b/google/cloud/bigtable/internal/logging_data_client.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace btproto = ::google::bigtable::v2;
@@ -179,7 +179,7 @@ LoggingDataClient::PrepareAsyncMutateRows(
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_data_client.h b/google/cloud/bigtable/internal/logging_data_client.h
index 2c1b61921520b..7c5a9ff90e6a4 100644
--- a/google/cloud/bigtable/internal/logging_data_client.h
+++ b/google/cloud/bigtable/internal/logging_data_client.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace btproto = ::google::bigtable::v2;
@@ -146,7 +146,7 @@ class LoggingDataClient : public DataClient {
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_data_client_test.cc b/google/cloud/bigtable/internal/logging_data_client_test.cc
index 732d453d0ced8..5b7f630520339 100644
--- a/google/cloud/bigtable/internal/logging_data_client_test.cc
+++ b/google/cloud/bigtable/internal/logging_data_client_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -154,7 +154,7 @@ TEST_F(LoggingDataClientTest, MutateRows) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_instance_admin_client.cc b/google/cloud/bigtable/internal/logging_instance_admin_client.cc
index 26236fa25d731..0d0ba463f88c7 100644
--- a/google/cloud/bigtable/internal/logging_instance_admin_client.cc
+++ b/google/cloud/bigtable/internal/logging_instance_admin_client.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace btadmin = ::google::bigtable::admin::v2;
@@ -433,7 +433,7 @@ LoggingInstanceAdminClient::AsyncGetOperation(
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_instance_admin_client.h b/google/cloud/bigtable/internal/logging_instance_admin_client.h
index 9ac5963aa5abd..aeb88fc7be3b3 100644
--- a/google/cloud/bigtable/internal/logging_instance_admin_client.h
+++ b/google/cloud/bigtable/internal/logging_instance_admin_client.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -292,7 +292,7 @@ class LoggingInstanceAdminClient
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/logging_instance_admin_client_test.cc b/google/cloud/bigtable/internal/logging_instance_admin_client_test.cc
index 2a99f299caa5a..caab384a4319e 100644
--- a/google/cloud/bigtable/internal/logging_instance_admin_client_test.cc
+++ b/google/cloud/bigtable/internal/logging_instance_admin_client_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -436,7 +436,7 @@ TEST_F(LoggingInstanceAdminClientTest, AsyncUpdateInstance) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/prefix_range_end.cc b/google/cloud/bigtable/internal/prefix_range_end.cc
index 311bfc7702049..e8eee6f5db06a 100644
--- a/google/cloud/bigtable/internal/prefix_range_end.cc
+++ b/google/cloud/bigtable/internal/prefix_range_end.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::string PrefixRangeEnd(std::string const& key) {
@@ -38,7 +38,7 @@ std::string PrefixRangeEnd(std::string const& key) {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/prefix_range_end.h b/google/cloud/bigtable/internal/prefix_range_end.h
index 1d920189d65d3..d20fbd99639cf 100644
--- a/google/cloud/bigtable/internal/prefix_range_end.h
+++ b/google/cloud/bigtable/internal/prefix_range_end.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Return the end of the prefix range for @p key.
@@ -34,7 +34,7 @@ namespace internal {
 std::string PrefixRangeEnd(std::string const& key);
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/prefix_range_end_test.cc b/google/cloud/bigtable/internal/prefix_range_end_test.cc
index a67ade02b7bd2..14dcde4256c77 100644
--- a/google/cloud/bigtable/internal/prefix_range_end_test.cc
+++ b/google/cloud/bigtable/internal/prefix_range_end_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -43,7 +43,7 @@ TEST(PrefixRangeEndTest, MostlyFFs) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/readrowsparser.cc b/google/cloud/bigtable/internal/readrowsparser.cc
index 6d976ddc94fb0..0808b632d10fe 100644
--- a/google/cloud/bigtable/internal/readrowsparser.cc
+++ b/google/cloud/bigtable/internal/readrowsparser.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 using ::google::bigtable::v2::ReadRowsResponse_CellChunk;
 
@@ -176,7 +176,7 @@ Cell ReadRowsParser::MovePartialToCell() {
   return cell;
 }
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/readrowsparser.h b/google/cloud/bigtable/internal/readrowsparser.h
index 0f29b273bb6f7..0563d128f277b 100644
--- a/google/cloud/bigtable/internal/readrowsparser.h
+++ b/google/cloud/bigtable/internal/readrowsparser.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Transforms a stream of chunks as returned by the ReadRows streaming
@@ -133,7 +133,7 @@ class ReadRowsParserFactory {
   }
 };
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/readrowsparser_test.cc b/google/cloud/bigtable/internal/readrowsparser_test.cc
index 8408fab5cc28b..1abd6c0a27784 100644
--- a/google/cloud/bigtable/internal/readrowsparser_test.cc
+++ b/google/cloud/bigtable/internal/readrowsparser_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -223,7 +223,7 @@ class AcceptanceTest : public ::testing::Test {
 
 }  // namespace
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/rowreaderiterator.cc b/google/cloud/bigtable/internal/rowreaderiterator.cc
index 93c462bd15564..f797fc6a98572 100644
--- a/google/cloud/bigtable/internal/rowreaderiterator.cc
+++ b/google/cloud/bigtable/internal/rowreaderiterator.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 RowReaderIterator::RowReaderIterator(RowReader* owner) : owner_(owner) {
@@ -57,7 +57,7 @@ void RowReaderIterator::Advance() {
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/rowreaderiterator.h b/google/cloud/bigtable/internal/rowreaderiterator.h
index cac75f495fa11..12b1fb1ad4f2d 100644
--- a/google/cloud/bigtable/internal/rowreaderiterator.h
+++ b/google/cloud/bigtable/internal/rowreaderiterator.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // Forward declare the owner class of this iterator.
 class RowReader;
 
@@ -85,7 +85,7 @@ inline bool operator!=(RowReaderIterator const& lhs,
 }
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/rpc_policy_parameters.h b/google/cloud/bigtable/internal/rpc_policy_parameters.h
index b3f4daab3cb22..b5829dec9a3ad 100644
--- a/google/cloud/bigtable/internal/rpc_policy_parameters.h
+++ b/google/cloud/bigtable/internal/rpc_policy_parameters.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /// Configuration parameters for retry and backoff policies.
@@ -34,7 +34,7 @@ struct RPCPolicyParameters {
 #include "google/cloud/bigtable/internal/rpc_policy_parameters.inc"
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/internal/unary_client_utils.h b/google/cloud/bigtable/internal/unary_client_utils.h
index b315678ccd375..10d299f48c680 100644
--- a/google/cloud/bigtable/internal/unary_client_utils.h
+++ b/google/cloud/bigtable/internal/unary_client_utils.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Helper functions to make (unary) gRPC calls under the right policies.
@@ -213,7 +213,7 @@ struct UnaryClientUtils {
 };
 
 }  // namespace internal
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/metadata_update_policy.cc b/google/cloud/bigtable/metadata_update_policy.cc
index ce0604442820c..91e99bfceec6e 100644
--- a/google/cloud/bigtable/metadata_update_policy.cc
+++ b/google/cloud/bigtable/metadata_update_policy.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // These we cannot change because they are part of the public API.
 // NOLINTNEXTLINE(readability-identifier-naming)
 MetadataParamTypes const MetadataParamTypes::PARENT("parent");
@@ -48,7 +48,7 @@ void MetadataUpdatePolicy::Setup(grpc::ClientContext& context) const {
   context.AddMetadata(std::string("x-goog-api-client"), api_client_header());
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/metadata_update_policy.h b/google/cloud/bigtable/metadata_update_policy.h
index 00126c80746b6..757a03d5ffd9c 100644
--- a/google/cloud/bigtable/metadata_update_policy.h
+++ b/google/cloud/bigtable/metadata_update_policy.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define the class for governing x-goog-request-params metadata value.
  *
@@ -102,7 +102,7 @@ class MetadataUpdatePolicy {
   std::string api_client_header_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/metadata_update_policy_test.cc b/google/cloud/bigtable/metadata_update_policy_test.cc
index fb6abc6447c43..4e8d1ba6c5903 100644
--- a/google/cloud/bigtable/metadata_update_policy_test.cc
+++ b/google/cloud/bigtable/metadata_update_policy_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class MetadataUpdatePolicyTest : public testing::EmbeddedServerTestFixture {};
@@ -79,7 +79,7 @@ TEST_F(MetadataUpdatePolicyTest, SimpleDefault) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/mutation_batcher.cc b/google/cloud/bigtable/mutation_batcher.cc
index d0c0f3c573d16..40292f42762be 100644
--- a/google/cloud/bigtable/mutation_batcher.cc
+++ b/google/cloud/bigtable/mutation_batcher.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 // Cloud Bigtable doesn't accept more than this in a single request.
 auto constexpr kBigtableMutationLimit = 100000;
@@ -284,7 +284,7 @@ void MutationBatcher::SatisfyPromises(
   }
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/mutation_batcher.h b/google/cloud/bigtable/mutation_batcher.h
index 3d1d0a47ae72a..baf7a391e9a76 100644
--- a/google/cloud/bigtable/mutation_batcher.h
+++ b/google/cloud/bigtable/mutation_batcher.h
@@ -32,7 +32,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Objects of this class pack single row mutations into bulk mutations.
  *
@@ -314,7 +314,7 @@ class MutationBatcher {
   std::vector<NoMorePendingPromise> no_more_pending_promises_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/mutation_batcher_test.cc b/google/cloud/bigtable/mutation_batcher_test.cc
index 75c39ac01e147..3a38c51a9c474 100644
--- a/google/cloud/bigtable/mutation_batcher_test.cc
+++ b/google/cloud/bigtable/mutation_batcher_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -839,7 +839,7 @@ TEST_F(MutationBatcherTest, ApplyCompletesImmediately) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/mutations.cc b/google/cloud/bigtable/mutations.cc
index 7cb9f970319b4..c1e6e75c07d0f 100644
--- a/google/cloud/bigtable/mutations.cc
+++ b/google/cloud/bigtable/mutations.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 Mutation DeleteFromFamily(std::string family) {
   Mutation m;
   auto& d = *m.op.mutable_delete_from_family();
@@ -42,7 +42,7 @@ Mutation SetCell(Cell cell) {
   return m;
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/mutations.h b/google/cloud/bigtable/mutations.h
index dfc03e374f997..21619afbe69e1 100644
--- a/google/cloud/bigtable/mutations.h
+++ b/google/cloud/bigtable/mutations.h
@@ -34,7 +34,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Represent a single change to a specific row in a Table.
  *
@@ -553,7 +553,7 @@ class BulkMutation {
   google::bigtable::v2::MutateRowsRequest request_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/mutations_test.cc b/google/cloud/bigtable/mutations_test.cc
index c0cb0ba0bd689..9e5a2c84b42b0 100644
--- a/google/cloud/bigtable/mutations_test.cc
+++ b/google/cloud/bigtable/mutations_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -271,7 +271,7 @@ TEST(MutationsTest, SingleRowMutationClear) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/options.h b/google/cloud/bigtable/options.h
index be55014f4e107..2cde4b7366981 100644
--- a/google/cloud/bigtable/options.h
+++ b/google/cloud/bigtable/options.h
@@ -46,7 +46,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// The endpoint for data operations.
 struct DataEndpointOption {
@@ -98,7 +98,7 @@ using ClientOptionList =
                InstanceAdminEndpointOption, MinConnectionRefreshOption,
                MaxConnectionRefreshOption>;
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/polling_policy.cc b/google/cloud/bigtable/polling_policy.cc
index 64b8233b84778..b7a73bb816fef 100644
--- a/google/cloud/bigtable/polling_policy.cc
+++ b/google/cloud/bigtable/polling_policy.cc
@@ -17,13 +17,13 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::unique_ptr<PollingPolicy> DefaultPollingPolicy(
     internal::RPCPolicyParameters defaults) {
   return std::unique_ptr<PollingPolicy>(new GenericPollingPolicy<>(defaults));
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/polling_policy.h b/google/cloud/bigtable/polling_policy.h
index 4026e821cd388..d5956ea63323b 100644
--- a/google/cloud/bigtable/polling_policy.h
+++ b/google/cloud/bigtable/polling_policy.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define the interface for providing asynchronous repetitive call rules
  *
@@ -146,7 +146,7 @@ class GenericPollingPolicy : public PollingPolicy {
 std::unique_ptr<PollingPolicy> DefaultPollingPolicy(
     internal::RPCPolicyParameters defaults);
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/read_modify_write_rule.h b/google/cloud/bigtable/read_modify_write_rule.h
index e3969be86c00d..7092b349fddd6 100644
--- a/google/cloud/bigtable/read_modify_write_rule.h
+++ b/google/cloud/bigtable/read_modify_write_rule.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define the interfaces to create ReadWriteModifyRule operations.
  *
@@ -82,7 +82,7 @@ class ReadModifyWriteRule {
   google::bigtable::v2::ReadModifyWriteRule rule_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/read_modify_write_rule_test.cc b/google/cloud/bigtable/read_modify_write_rule_test.cc
index 6209a2276443f..0d5fe19aeda0c 100644
--- a/google/cloud/bigtable/read_modify_write_rule_test.cc
+++ b/google/cloud/bigtable/read_modify_write_rule_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -42,7 +42,7 @@ TEST(ReadModifyWriteRuleTest, IncrementAmount) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/resource_names.cc b/google/cloud/bigtable/resource_names.cc
index 85094b2305327..56ba86cc75d95 100644
--- a/google/cloud/bigtable/resource_names.cc
+++ b/google/cloud/bigtable/resource_names.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string InstanceName(std::string const& project_id,
                          std::string const& instance_id) {
@@ -54,7 +54,7 @@ std::string BackupName(std::string const& project_id,
                       "/backups/", backup_id);
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/resource_names.h b/google/cloud/bigtable/resource_names.h
index 109f5d21ca869..c4683f52482d5 100644
--- a/google/cloud/bigtable/resource_names.h
+++ b/google/cloud/bigtable/resource_names.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * @file
@@ -49,7 +49,7 @@ std::string BackupName(std::string const& project_id,
                        std::string const& cluster_id,
                        std::string const& backup_id);
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row.h b/google/cloud/bigtable/row.h
index 6f8e92b4d9673..1e874dd0172f2 100644
--- a/google/cloud/bigtable/row.h
+++ b/google/cloud/bigtable/row.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * The in-memory representation of a Bigtable row.
  *
@@ -52,7 +52,7 @@ class Row {
   std::vector<Cell> cells_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_key.h b/google/cloud/bigtable/row_key.h
index 04b21c11019f0..8c97f6bc002ed 100644
--- a/google/cloud/bigtable/row_key.h
+++ b/google/cloud/bigtable/row_key.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Defines the type for row keys.
  *
@@ -47,7 +47,7 @@ inline namespace BIGTABLE_CLIENT_NS {
 using RowKeyType =
     std::decay<decltype(std::declval<google::bigtable::v2::Row>().key())>::type;
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_key_sample.h b/google/cloud/bigtable/row_key_sample.h
index 24401ad1388f3..d2fde5ab96e43 100644
--- a/google/cloud/bigtable/row_key_sample.h
+++ b/google/cloud/bigtable/row_key_sample.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// A simple wrapper to represent the response from `Table::SampleRowKeys()`.
 struct RowKeySample {
   /**
@@ -41,7 +41,7 @@ struct RowKeySample {
   std::int64_t offset_bytes;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_range.cc b/google/cloud/bigtable/row_range.cc
index f267f5d95bd1e..21e2341a33add 100644
--- a/google/cloud/bigtable/row_range.cc
+++ b/google/cloud/bigtable/row_range.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace btproto = ::google::bigtable::v2;
 
 bool RowRange::IsEmpty() const {
@@ -232,7 +232,7 @@ std::ostream& operator<<(std::ostream& os, RowRange const& x) {
   return os;
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_range.h b/google/cloud/bigtable/row_range.h
index 4b795f0932e82..ceb4ac2c75a99 100644
--- a/google/cloud/bigtable/row_range.h
+++ b/google/cloud/bigtable/row_range.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define the interfaces to create row key ranges.
  *
@@ -201,7 +201,7 @@ inline bool operator!=(RowRange const& lhs, RowRange const& rhs) {
 
 /// Print a human-readable representation of the range, mostly for testing.
 std::ostream& operator<<(std::ostream& os, RowRange const& x);
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_range_test.cc b/google/cloud/bigtable/row_range_test.cc
index e9864fb1e83e6..229ec1d701a20 100644
--- a/google/cloud/bigtable/row_range_test.cc
+++ b/google/cloud/bigtable/row_range_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -736,7 +736,7 @@ TEST(RowRangeTest, IntersectEndingAtEndingAt) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_reader.cc b/google/cloud/bigtable/row_reader.cc
index 15f8db5e56591..dcccd25f719ee 100644
--- a/google/cloud/bigtable/row_reader.cc
+++ b/google/cloud/bigtable/row_reader.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // RowReader::iterator must satisfy the requirements of an InputIterator.
 static_assert(
     std::is_same<std::iterator_traits<RowReader::iterator>::iterator_category,
@@ -248,7 +248,7 @@ RowReader::~RowReader() {
   // Make sure we don't leave open streams.
   Cancel();
 }
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_reader.h b/google/cloud/bigtable/row_reader.h
index 23004b98fdabf..a28ed253a1323 100644
--- a/google/cloud/bigtable/row_reader.h
+++ b/google/cloud/bigtable/row_reader.h
@@ -36,7 +36,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Object returned by Table::ReadRows(), enumerates rows in the response.
  *
@@ -166,7 +166,7 @@ class RowReader {
   RowKeyType last_read_row_key_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_reader_test.cc b/google/cloud/bigtable/row_reader_test.cc
index c2156cfb6e8bf..c60f5141115f9 100644
--- a/google/cloud/bigtable/row_reader_test.cc
+++ b/google/cloud/bigtable/row_reader_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::bigtable::v2::ReadRowsRequest;
@@ -785,7 +785,7 @@ TEST_F(RowReaderTest, FailedStreamRetryNewContext) {
 }
 
 }  // anonymous namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_set.cc b/google/cloud/bigtable/row_set.cc
index 19ba29f15336d..474f76b0aba92 100644
--- a/google/cloud/bigtable/row_set.cc
+++ b/google/cloud/bigtable/row_set.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 RowSet RowSet::Intersect(bigtable::RowRange const& range) const {
   // Special case: "all rows", return the argument range.
   if (row_set_.row_keys().empty() && row_set_.row_ranges().empty()) {
@@ -59,7 +59,7 @@ bool RowSet::IsEmpty() const {
   // (meaning "all rows").
   return row_set_.row_ranges_size() > 0;
 }
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_set.h b/google/cloud/bigtable/row_set.h
index b5a63ffc4f3c6..a96bf29c9bb42 100644
--- a/google/cloud/bigtable/row_set.h
+++ b/google/cloud/bigtable/row_set.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Represent a (possibly non-continuous) set of row keys.
  *
@@ -95,7 +95,7 @@ class RowSet {
 
   ::google::bigtable::v2::RowSet row_set_;
 };
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_set_test.cc b/google/cloud/bigtable/row_set_test.cc
index af4bb1af2b489..9b46776eb682f 100644
--- a/google/cloud/bigtable/row_set_test.cc
+++ b/google/cloud/bigtable/row_set_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(RowSetTest, DefaultConstructor) {
@@ -116,7 +116,7 @@ TEST(RowSetTest, IntersectWithDisjointIsEmpty) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/row_test.cc b/google/cloud/bigtable/row_test.cc
index e7e23a93a4eff..f79096bed40a4 100644
--- a/google/cloud/bigtable/row_test.cc
+++ b/google/cloud/bigtable/row_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 /// @test Verify Row instantiation and trivial accessors.
@@ -59,7 +59,7 @@ TEST(RowTest, MoveOverload) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/rpc_backoff_policy.cc b/google/cloud/bigtable/rpc_backoff_policy.cc
index 43d26ff00b4ba..d314b3b69a904 100644
--- a/google/cloud/bigtable/rpc_backoff_policy.cc
+++ b/google/cloud/bigtable/rpc_backoff_policy.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::unique_ptr<RPCBackoffPolicy> DefaultRPCBackoffPolicy(
     internal::RPCPolicyParameters defaults) {
   return std::unique_ptr<RPCBackoffPolicy>(new ExponentialBackoffPolicy(
@@ -45,7 +45,7 @@ std::chrono::milliseconds ExponentialBackoffPolicy::OnCompletion(
   return impl_.OnCompletion();
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/rpc_backoff_policy.h b/google/cloud/bigtable/rpc_backoff_policy.h
index d06eaa6056e5b..495ac83d1da8f 100644
--- a/google/cloud/bigtable/rpc_backoff_policy.h
+++ b/google/cloud/bigtable/rpc_backoff_policy.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define the interface for controlling how the Bigtable client
  * backsoff from failed RPC operations.
@@ -103,7 +103,7 @@ class ExponentialBackoffPolicy : public RPCBackoffPolicy {
   Impl impl_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/rpc_backoff_policy_test.cc b/google/cloud/bigtable/rpc_backoff_policy_test.cc
index ee4275be19848..0272663e7ac83 100644
--- a/google/cloud/bigtable/rpc_backoff_policy_test.cc
+++ b/google/cloud/bigtable/rpc_backoff_policy_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _ms;
@@ -74,7 +74,7 @@ TEST(ExponentialBackoffRetryPolicy, Randomness) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/rpc_retry_policy.cc b/google/cloud/bigtable/rpc_retry_policy.cc
index df634b7c6c9d0..21facadec225c 100644
--- a/google/cloud/bigtable/rpc_retry_policy.cc
+++ b/google/cloud/bigtable/rpc_retry_policy.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::unique_ptr<RPCRetryPolicy> DefaultRPCRetryPolicy(
     internal::RPCPolicyParameters defaults) {
@@ -65,7 +65,7 @@ bool LimitedTimeRetryPolicy::OnFailure(grpc::Status const& status) {
   return impl_.OnFailure(MakeStatusFromRpcError(status));
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/rpc_retry_policy.h b/google/cloud/bigtable/rpc_retry_policy.h
index a6e775f28af68..44c60e1a697a2 100644
--- a/google/cloud/bigtable/rpc_retry_policy.h
+++ b/google/cloud/bigtable/rpc_retry_policy.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// An adapter to use `grpc::Status` with the `google::cloud::*Policies`.
 struct SafeGrpcRetry {
@@ -155,7 +155,7 @@ class LimitedTimeRetryPolicy : public RPCRetryPolicy {
   Impl impl_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/rpc_retry_policy_test.cc b/google/cloud/bigtable/rpc_retry_policy_test.cc
index cdb6d11d836e2..d376b5fde579e 100644
--- a/google/cloud/bigtable/rpc_retry_policy_test.cc
+++ b/google/cloud/bigtable/rpc_retry_policy_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 /// Create a grpc::Status with a status code for transient errors.
@@ -115,7 +115,7 @@ TEST(TransientInternalError, RstStreamRetried) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table.cc b/google/cloud/bigtable/table.cc
index b6726b061d315..963a9fa8f36b9 100644
--- a/google/cloud/bigtable/table.cc
+++ b/google/cloud/bigtable/table.cc
@@ -25,7 +25,7 @@ namespace btproto = ::google::bigtable::v2;
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::Idempotency;
 
@@ -454,7 +454,7 @@ future<StatusOr<std::pair<bool, Row>>> Table::AsyncReadRow(std::string row_key,
   return handler->GetFuture();
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table.h b/google/cloud/bigtable/table.h
index 064a159c933f5..e6774bc3dc26a 100644
--- a/google/cloud/bigtable/table.h
+++ b/google/cloud/bigtable/table.h
@@ -39,7 +39,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// The branch taken by a Table::CheckAndMutateRow operation.
 enum class MutationBranch {
   /// The predicate provided to CheckAndMutateRow did not match and the
@@ -910,7 +910,7 @@ class Table {
   std::shared_ptr<BackgroundThreads> background_threads_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_admin.cc b/google/cloud/bigtable/table_admin.cc
index 0db5e0296b249..c16b740812887 100644
--- a/google/cloud/bigtable/table_admin.cc
+++ b/google/cloud/bigtable/table_admin.cc
@@ -29,7 +29,7 @@ namespace btadmin = ::google::bigtable::admin::v2;
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 static_assert(std::is_copy_constructible<bigtable::TableAdmin>::value,
               "bigtable::TableAdmin must be constructible");
 static_assert(std::is_copy_assignable<bigtable::TableAdmin>::value,
@@ -751,7 +751,7 @@ std::string TableAdmin::InstanceName() const {
                                                instance_id_);
 }
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_admin.h b/google/cloud/bigtable/table_admin.h
index a0cdfcaf18025..f39ca2be50377 100644
--- a/google/cloud/bigtable/table_admin.h
+++ b/google/cloud/bigtable/table_admin.h
@@ -39,7 +39,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// The result of checking replication against a given token.
 enum class Consistency {
   /// Some of the mutations created before the consistency token have not been
@@ -1076,7 +1076,7 @@ class TableAdmin {
   std::shared_ptr<BackgroundThreads> background_threads_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_admin_test.cc b/google/cloud/bigtable/table_admin_test.cc
index 3029aa70bfd4c..c058ae6c6325e 100644
--- a/google/cloud/bigtable/table_admin_test.cc
+++ b/google/cloud/bigtable/table_admin_test.cc
@@ -32,7 +32,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class TableAdminTester {
  public:
@@ -1422,7 +1422,7 @@ TEST_F(ValidContextMdAsyncTest, AsyncRestoreTable) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_apply_test.cc b/google/cloud/bigtable/table_apply_test.cc
index 94f11976c3b8a..22c1857b1854b 100644
--- a/google/cloud/bigtable/table_apply_test.cc
+++ b/google/cloud/bigtable/table_apply_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace bigtable = ::google::cloud::bigtable;
@@ -94,7 +94,7 @@ TEST_F(TableApplyTest, RetryIdempotent) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_bulk_apply_test.cc b/google/cloud/bigtable/table_bulk_apply_test.cc
index 0e2791da4d8d0..6865176c26450 100644
--- a/google/cloud/bigtable/table_bulk_apply_test.cc
+++ b/google/cloud/bigtable/table_bulk_apply_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -301,7 +301,7 @@ TEST_F(TableBulkApplyTest, FailedRPC) {
 }
 
 }  // anonymous namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_check_and_mutate_row_test.cc b/google/cloud/bigtable/table_check_and_mutate_row_test.cc
index 582ba1dfc0102..622a0a4f148a6 100644
--- a/google/cloud/bigtable/table_check_and_mutate_row_test.cc
+++ b/google/cloud/bigtable/table_check_and_mutate_row_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsContextMDValid;
@@ -72,7 +72,7 @@ TEST_F(TableCheckAndMutateRowTest, Failure) {
 #endif  // GOOGLE_CLOUD_CPP_HAVE_EXCEPTIONS
 
 }  // anonymous namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_config.cc b/google/cloud/bigtable/table_config.cc
index 17cddbf7222be..8dcf23b6b6c81 100644
--- a/google/cloud/bigtable/table_config.cc
+++ b/google/cloud/bigtable/table_config.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // NOLINTNEXTLINE(readability-identifier-naming)
 ::google::bigtable::admin::v2::CreateTableRequest TableConfig::as_proto() && {
   // As a challenge, we implement the strong exception guarantee in this
@@ -62,7 +62,7 @@ constexpr TableConfig::TimestampGranularity TableConfig::MILLIS;  // NOLINT
 constexpr TableConfig::TimestampGranularity
     TableConfig::TIMESTAMP_GRANULARITY_UNSPECIFIED;  // NOLINT
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_config.h b/google/cloud/bigtable/table_config.h
index 5a06bb8d4d775..e9e99b014e722 100644
--- a/google/cloud/bigtable/table_config.h
+++ b/google/cloud/bigtable/table_config.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// Specify the initial schema for a new table.
 class TableConfig {
  public:
@@ -96,7 +96,7 @@ class TableConfig {
   ::google::bigtable::admin::v2::Table::TimestampGranularity granularity_;
 };
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_config_test.cc b/google/cloud/bigtable/table_config_test.cc
index 81d9a6f8b115a..e2f7e54c20b05 100644
--- a/google/cloud/bigtable/table_config_test.cc
+++ b/google/cloud/bigtable/table_config_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btadmin = ::google::bigtable::admin::v2;
@@ -81,7 +81,7 @@ TEST(TableConfig, ComplexConstructor) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_readmodifywriterow_test.cc b/google/cloud/bigtable/table_readmodifywriterow_test.cc
index 2aab8e5d80802..8ff14f85d1cf6 100644
--- a/google/cloud/bigtable/table_readmodifywriterow_test.cc
+++ b/google/cloud/bigtable/table_readmodifywriterow_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -284,7 +284,7 @@ TEST_F(TableReadModifyWriteTest, UnrecoverableFailureTest) {
 }
 
 }  // anonymous namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_readrow_test.cc b/google/cloud/bigtable/table_readrow_test.cc
index b5630e79de573..d606fd51699d5 100644
--- a/google/cloud/bigtable/table_readrow_test.cc
+++ b/google/cloud/bigtable/table_readrow_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -122,7 +122,7 @@ TEST_F(TableReadRowTest, UnrecoverableFailure) {
 }
 
 }  // anonymous namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_readrows_test.cc b/google/cloud/bigtable/table_readrows_test.cc
index 1dab48cea6bb0..8acff769e0d5d 100644
--- a/google/cloud/bigtable/table_readrows_test.cc
+++ b/google/cloud/bigtable/table_readrows_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::bigtable::testing::MockReadRowsReader;
@@ -152,7 +152,7 @@ TEST_F(TableReadRowsTest, ReadRowsThrowsWhenTooManyErrors) {
 }
 
 }  // anonymous namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_sample_row_keys_test.cc b/google/cloud/bigtable/table_sample_row_keys_test.cc
index 9c499b5f919de..0638fed260a01 100644
--- a/google/cloud/bigtable/table_sample_row_keys_test.cc
+++ b/google/cloud/bigtable/table_sample_row_keys_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _us;
@@ -173,7 +173,7 @@ TEST_F(TableSampleRowKeysTest, TooManyFailures) {
 #endif  // GOOGLE_CLOUD_CPP_HAVE_EXCEPTIONS
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/table_test.cc b/google/cloud/bigtable/table_test.cc
index 6b71d270d1255..925336dc9bc6f 100644
--- a/google/cloud/bigtable/table_test.cc
+++ b/google/cloud/bigtable/table_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace btproto = ::google::bigtable::v2;
@@ -216,7 +216,7 @@ TEST_F(ValidContextMdAsyncTest, AsyncReadModifyWriteRow) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/admin_backup_integration_test.cc b/google/cloud/bigtable/tests/admin_backup_integration_test.cc
index 2acbf0195faf5..990f763861c4f 100644
--- a/google/cloud/bigtable/tests/admin_backup_integration_test.cc
+++ b/google/cloud/bigtable/tests/admin_backup_integration_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::ContainsOnce;
@@ -173,7 +173,7 @@ TEST_F(AdminBackupIntegrationTest, CreateListGetUpdateRestoreDeleteBackup) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/admin_iam_policy_integration_test.cc b/google/cloud/bigtable/tests/admin_iam_policy_integration_test.cc
index 8df3e5ef19cba..7939ebfc7e6e6 100644
--- a/google/cloud/bigtable/tests/admin_iam_policy_integration_test.cc
+++ b/google/cloud/bigtable/tests/admin_iam_policy_integration_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -96,7 +96,7 @@ TEST_F(AdminIAMPolicyIntegrationTest, SetGetTestIamAPIsTest) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/admin_integration_test.cc b/google/cloud/bigtable/tests/admin_integration_test.cc
index becc94ccc5907..8d69a4e6dee7d 100644
--- a/google/cloud/bigtable/tests/admin_integration_test.cc
+++ b/google/cloud/bigtable/tests/admin_integration_test.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::ContainsOnce;
@@ -403,7 +403,7 @@ TEST_F(AdminIntegrationTest, CreateListGetDeleteTableWithLogging) {
   EXPECT_THAT(log_lines, Contains(HasSubstr("DeleteTable")));
 }
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/data_async_future_integration_test.cc b/google/cloud/bigtable/tests/data_async_future_integration_test.cc
index 485b11ae98c09..398e2c1147cf4 100644
--- a/google/cloud/bigtable/tests/data_async_future_integration_test.cc
+++ b/google/cloud/bigtable/tests/data_async_future_integration_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 using ::google::cloud::testing_util::chrono_literals::operator"" _ms;
 using DataAsyncFutureIntegrationTest = bigtable::testing::TableIntegrationTest;
@@ -279,7 +279,7 @@ TEST_F(DataAsyncFutureIntegrationTest, TableReadRowTest) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/data_integration_test.cc b/google/cloud/bigtable/tests/data_integration_test.cc
index 49f9daca05d8a..bbfa155c89783 100644
--- a/google/cloud/bigtable/tests/data_integration_test.cc
+++ b/google/cloud/bigtable/tests/data_integration_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _ms;
@@ -617,7 +617,7 @@ TEST(ConnectionRefresh, Frequent) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/filters_integration_test.cc b/google/cloud/bigtable/tests/filters_integration_test.cc
index 168815d1d3c1f..c221888982b79 100644
--- a/google/cloud/bigtable/tests/filters_integration_test.cc
+++ b/google/cloud/bigtable/tests/filters_integration_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::ContainerEq;
@@ -604,7 +604,7 @@ TEST_F(FilterIntegrationTest, InterleaveFromRange) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/instance_admin_integration_test.cc b/google/cloud/bigtable/tests/instance_admin_integration_test.cc
index 4d6b4acefb1de..44ff366913a9d 100644
--- a/google/cloud/bigtable/tests/instance_admin_integration_test.cc
+++ b/google/cloud/bigtable/tests/instance_admin_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::ContainsOnce;
@@ -530,7 +530,7 @@ TEST_F(InstanceAdminIntegrationTest, CustomWorkers) {
 }
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/mutations_integration_test.cc b/google/cloud/bigtable/tests/mutations_integration_test.cc
index 5fce8b5a90c4e..1e34982ed7334 100644
--- a/google/cloud/bigtable/tests/mutations_integration_test.cc
+++ b/google/cloud/bigtable/tests/mutations_integration_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -441,7 +441,7 @@ TEST_F(MutationIntegrationTest, DeleteFromRowTest) {
 // Test Cases Finished
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/tests/table_sample_rows_integration_test.cc b/google/cloud/bigtable/tests/table_sample_rows_integration_test.cc
index 2f66c53d3333d..5c1b5b64f1668 100644
--- a/google/cloud/bigtable/tests/table_sample_rows_integration_test.cc
+++ b/google/cloud/bigtable/tests/table_sample_rows_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::bigtable::testing::TableTestEnvironment;
@@ -121,7 +121,7 @@ TEST_F(SampleRowsIntegrationTest, Asynchronous) {
 };
 
 }  // namespace
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/version.cc b/google/cloud/bigtable/version.cc
index 98e94a03ec50d..71914a875cc1f 100644
--- a/google/cloud/bigtable/version.cc
+++ b/google/cloud/bigtable/version.cc
@@ -19,9 +19,9 @@
 namespace google {
 namespace cloud {
 namespace bigtable {
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::string version_string() { return ::google::cloud::version_string(); }
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/bigtable/version.h b/google/cloud/bigtable/version.h
index 6fb2799327f82..6c09038b02fc0 100644
--- a/google/cloud/bigtable/version.h
+++ b/google/cloud/bigtable/version.h
@@ -27,6 +27,9 @@
       " instead. The function will be removed on 2022-04-01 or shortly "       \
       "after. See GitHub issue #5929 for more information.")
 
+// This preprocessor symbol is deprecated and should never be used anywhere. It
+// exists solely for backward compatibility to avoid breaking anyone who may
+// have been using it.
 #define BIGTABLE_CLIENT_NS GOOGLE_CLOUD_CPP_NS
 
 namespace google {
@@ -47,7 +50,7 @@ namespace bigtable {
  * Note that, consistent with the semver.org guidelines, the v0 version makes
  * no guarantees with respect to backwards compatibility.
  */
-inline namespace BIGTABLE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * The Cloud Bigtable C++ Client major version.
  *
@@ -75,7 +78,7 @@ int constexpr version() { return google::cloud::version(); }
 /// The version as a string, in MAJOR.MINOR.PATCH+gitrev format.
 std::string version_string();
 
-}  // namespace BIGTABLE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace bigtable
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/ack_handler.cc b/google/cloud/pubsub/ack_handler.cc
index ed6fe7487c339..4553e83924529 100644
--- a/google/cloud/pubsub/ack_handler.cc
+++ b/google/cloud/pubsub/ack_handler.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 static_assert(!std::is_copy_assignable<AckHandler>::value,
               "AckHandler should not be CopyAssignable");
@@ -35,7 +35,7 @@ AckHandler::~AckHandler() {
 
 AckHandler::Impl::~Impl() = default;
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/ack_handler.h b/google/cloud/pubsub/ack_handler.h
index 5c165bdcd4250..8197632881924 100644
--- a/google/cloud/pubsub/ack_handler.h
+++ b/google/cloud/pubsub/ack_handler.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Defines the interface to acknowledge and reject messages.
@@ -107,7 +107,7 @@ class AckHandler {
   std::unique_ptr<Impl> impl_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/ack_handler_test.cc b/google/cloud/pubsub/ack_handler_test.cc
index 4b9eb0bffe410..09414193823df 100644
--- a/google/cloud/pubsub/ack_handler_test.cc
+++ b/google/cloud/pubsub/ack_handler_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Return;
@@ -64,7 +64,7 @@ TEST(AckHandlerTest, Nack) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/application_callback.h b/google/cloud/pubsub/application_callback.h
index 1aee770fbe59f..47febc1f86280 100644
--- a/google/cloud/pubsub/application_callback.h
+++ b/google/cloud/pubsub/application_callback.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class Message;
 class AckHandler;
 
@@ -34,7 +34,7 @@ class AckHandler;
  */
 using ApplicationCallback = std::function<void(Message, AckHandler)>;
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/backoff_policy.h b/google/cloud/pubsub/backoff_policy.h
index c34ada7b39067..f2421a0625501 100644
--- a/google/cloud/pubsub/backoff_policy.h
+++ b/google/cloud/pubsub/backoff_policy.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// The base class for backoff policies.
 using BackoffPolicy = ::google::cloud::internal::BackoffPolicy;
@@ -30,7 +30,7 @@ using BackoffPolicy = ::google::cloud::internal::BackoffPolicy;
 using ExponentialBackoffPolicy =
     google::cloud::internal::ExponentialBackoffPolicy;
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/connection_options.cc b/google/cloud/pubsub/connection_options.cc
index 0ece042a34ed7..f1007f3b1df1c 100644
--- a/google/cloud/pubsub/connection_options.cc
+++ b/google/cloud/pubsub/connection_options.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string ConnectionOptionsTraits::default_endpoint() {
   return "pubsub.googleapis.com";
@@ -34,7 +34,7 @@ int ConnectionOptionsTraits::default_num_channels() {
   return ncores == 0 ? 4 : static_cast<int>(ncores);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/connection_options.h b/google/cloud/pubsub/connection_options.h
index e5c719204f1c3..fc18a17e01a0f 100644
--- a/google/cloud/pubsub/connection_options.h
+++ b/google/cloud/pubsub/connection_options.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// The Cloud Pub/Sub connection traits.
 struct ConnectionOptionsTraits {
@@ -36,7 +36,7 @@ struct ConnectionOptionsTraits {
 using ConnectionOptions =
     ::google::cloud::ConnectionOptions<ConnectionOptionsTraits>;
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/integration_tests/schema_admin_integration_test.cc b/google/cloud/pubsub/integration_tests/schema_admin_integration_test.cc
index 99af51a797d7d..7fffa4a52503f 100644
--- a/google/cloud/pubsub/integration_tests/schema_admin_integration_test.cc
+++ b/google/cloud/pubsub/integration_tests/schema_admin_integration_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::pubsub_testing::MakeTestOptions;
@@ -169,7 +169,7 @@ TEST_F(SchemaAdminIntegrationTest, ValidateMessage) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/integration_tests/subscriber_integration_test.cc b/google/cloud/pubsub/integration_tests/subscriber_integration_test.cc
index 7d7e4c3829934..2f7e82a327aa0 100644
--- a/google/cloud/pubsub/integration_tests/subscriber_integration_test.cc
+++ b/google/cloud/pubsub/integration_tests/subscriber_integration_test.cc
@@ -36,7 +36,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -433,7 +433,7 @@ TEST_F(SubscriberIntegrationTest, PublishOrdered) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/integration_tests/subscription_admin_integration_test.cc b/google/cloud/pubsub/integration_tests/subscription_admin_integration_test.cc
index c689ae60c1bc4..a3fa9bc32947e 100644
--- a/google/cloud/pubsub/integration_tests/subscription_admin_integration_test.cc
+++ b/google/cloud/pubsub/integration_tests/subscription_admin_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::pubsub_testing::MakeTestOptions;
@@ -345,7 +345,7 @@ TEST_F(SubscriptionAdminIntegrationTest, SeekFailureSnapshot) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/integration_tests/topic_admin_integration_test.cc b/google/cloud/pubsub/integration_tests/topic_admin_integration_test.cc
index 0892f36a622c9..bb4af7934f627 100644
--- a/google/cloud/pubsub/integration_tests/topic_admin_integration_test.cc
+++ b/google/cloud/pubsub/integration_tests/topic_admin_integration_test.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::pubsub_testing::MakeTestOptions;
@@ -192,7 +192,7 @@ TEST_F(TopicAdminIntegrationTest, ListTopicSnapshotsFailure) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/batch_sink.h b/google/cloud/pubsub/internal/batch_sink.h
index e0a265046ee5a..02e3aed13c7dc 100644
--- a/google/cloud/pubsub/internal/batch_sink.h
+++ b/google/cloud/pubsub/internal/batch_sink.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Define the interface to push message batches to Cloud Pub/Sub.
@@ -46,7 +46,7 @@ class BatchSink {
   virtual void ResumePublish(std::string const& ordering_key) = 0;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/batching_publisher_connection.cc b/google/cloud/pubsub/internal/batching_publisher_connection.cc
index c91909c1ce46d..7dece41107eef 100644
--- a/google/cloud/pubsub/internal/batching_publisher_connection.cc
+++ b/google/cloud/pubsub/internal/batching_publisher_connection.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 // A helper callable to handle a response, it is a bit large for a lambda, and
 // we need move-capture anyways.
@@ -196,7 +196,7 @@ void BatchingPublisherConnection::FlushImpl(std::unique_lock<std::mutex> lk) {
   sink_->AsyncPublish(std::move(request)).then(std::move(batch));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/batching_publisher_connection.h b/google/cloud/pubsub/internal/batching_publisher_connection.h
index 28ae15b542cf8..5380f7593ea06 100644
--- a/google/cloud/pubsub/internal/batching_publisher_connection.h
+++ b/google/cloud/pubsub/internal/batching_publisher_connection.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class BatchingPublisherConnection
     : public pubsub::PublisherConnection,
@@ -83,7 +83,7 @@ class BatchingPublisherConnection
   Status corked_on_status_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/batching_publisher_connection_test.cc b/google/cloud/pubsub/internal/batching_publisher_connection_test.cc
index 359c1a7c2bfa4..7ab2e460b0736 100644
--- a/google/cloud/pubsub/internal/batching_publisher_connection_test.cc
+++ b/google/cloud/pubsub/internal/batching_publisher_connection_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::AsyncSequencer;
@@ -761,7 +761,7 @@ TEST(BatchingPublisherConnectionTest, HandleErrorWithOrderingResume) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/create_channel.cc b/google/cloud/pubsub/internal/create_channel.cc
index 870b28502fa80..f9cd2005a103b 100644
--- a/google/cloud/pubsub/internal/create_channel.cc
+++ b/google/cloud/pubsub/internal/create_channel.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<grpc::Channel> CreateChannel(Options const& opts,
                                              int channel_id) {
@@ -43,7 +43,7 @@ grpc::ChannelArguments MakeChannelArguments(Options const& opts,
   return args;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/create_channel.h b/google/cloud/pubsub/internal/create_channel.h
index 890b8fef75dc8..c3163ad397af8 100644
--- a/google/cloud/pubsub/internal/create_channel.h
+++ b/google/cloud/pubsub/internal/create_channel.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Create a gRPC channel with the right configuration.
 std::shared_ptr<grpc::Channel> CreateChannel(Options const& opts,
@@ -33,7 +33,7 @@ std::shared_ptr<grpc::Channel> CreateChannel(Options const& opts,
 grpc::ChannelArguments MakeChannelArguments(Options const& opts,
                                             int channel_id);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/default_batch_sink.cc b/google/cloud/pubsub/internal/default_batch_sink.cc
index f5e3f0d34beb1..92cb265aa54c4 100644
--- a/google/cloud/pubsub/internal/default_batch_sink.cc
+++ b/google/cloud/pubsub/internal/default_batch_sink.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 DefaultBatchSink::DefaultBatchSink(std::shared_ptr<PublisherStub> stub,
                                    CompletionQueue cq, Options const& opts)
@@ -43,7 +43,7 @@ DefaultBatchSink::AsyncPublish(google::pubsub::v1::PublishRequest request) {
 
 void DefaultBatchSink::ResumePublish(std::string const&) {}
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/default_batch_sink.h b/google/cloud/pubsub/internal/default_batch_sink.h
index 26bd2f7a09831..27cae4f3c8342 100644
--- a/google/cloud/pubsub/internal/default_batch_sink.h
+++ b/google/cloud/pubsub/internal/default_batch_sink.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Publish message batches using a stub, with retries, but no queueing.
 class DefaultBatchSink : public BatchSink {
@@ -55,7 +55,7 @@ class DefaultBatchSink : public BatchSink {
   std::unique_ptr<pubsub::BackoffPolicy const> backoff_policy_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/default_batch_sink_test.cc b/google/cloud/pubsub/internal/default_batch_sink_test.cc
index 55c692c754508..334eeea269718 100644
--- a/google/cloud/pubsub/internal/default_batch_sink_test.cc
+++ b/google/cloud/pubsub/internal/default_batch_sink_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -119,7 +119,7 @@ TEST(DefaultBatchSinkTest, TooManyTransients) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/defaults.cc b/google/cloud/pubsub/internal/defaults.cc
index 7b6a6b93872de..8392855e9793c 100644
--- a/google/cloud/pubsub/internal/defaults.cc
+++ b/google/cloud/pubsub/internal/defaults.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using std::chrono::seconds;
 using ms = std::chrono::milliseconds;
@@ -164,7 +164,7 @@ Options DefaultSubscriberOptionsOnly(Options opts) {
   return opts;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/defaults.h b/google/cloud/pubsub/internal/defaults.h
index afbc9e3ebb431..d213d8292f334 100644
--- a/google/cloud/pubsub/internal/defaults.h
+++ b/google/cloud/pubsub/internal/defaults.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::size_t DefaultThreadCount();
 
@@ -35,7 +35,7 @@ Options DefaultSubscriberOptions(Options opts);
 
 Options DefaultSubscriberOptionsOnly(Options opts);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/defaults_test.cc b/google/cloud/pubsub/internal/defaults_test.cc
index 4136186cf7447..307672c5e07e3 100644
--- a/google/cloud/pubsub/internal/defaults_test.cc
+++ b/google/cloud/pubsub/internal/defaults_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ms = std::chrono::milliseconds;
@@ -257,7 +257,7 @@ TEST(OptionsTest, DefaultPublisherOnly) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/flow_controlled_publisher_connection.cc b/google/cloud/pubsub/internal/flow_controlled_publisher_connection.cc
index d8821f6b32a42..a86dc38f57c33 100644
--- a/google/cloud/pubsub/internal/flow_controlled_publisher_connection.cc
+++ b/google/cloud/pubsub/internal/flow_controlled_publisher_connection.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 StatusOr<std::string> RejectMessage() {
   return Status(StatusCode::kFailedPrecondition, "Publisher is full");
@@ -66,7 +66,7 @@ void FlowControlledPublisherConnection::OnPublish(std::size_t message_size) {
   cv_.notify_all();
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/flow_controlled_publisher_connection.h b/google/cloud/pubsub/internal/flow_controlled_publisher_connection.h
index d894e4e23b79a..169fc8afb12a5 100644
--- a/google/cloud/pubsub/internal/flow_controlled_publisher_connection.h
+++ b/google/cloud/pubsub/internal/flow_controlled_publisher_connection.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class FlowControlledPublisherConnection
     : public pubsub::PublisherConnection,
@@ -97,7 +97,7 @@ class FlowControlledPublisherConnection
   std::size_t max_pending_messages_ = 0;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/flow_controlled_publisher_connection_test.cc b/google/cloud/pubsub/internal/flow_controlled_publisher_connection_test.cc
index ffddffb8afbc2..5a1a67b891a97 100644
--- a/google/cloud/pubsub/internal/flow_controlled_publisher_connection_test.cc
+++ b/google/cloud/pubsub/internal/flow_controlled_publisher_connection_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::pubsub_mocks::MockPublisherConnection;
@@ -242,7 +242,7 @@ TEST(FlowControlledPublisherConnection, NoDeadlockOnPublish) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/non_constructible.h b/google/cloud/pubsub/internal/non_constructible.h
index 6e33341e33357..44912d856736a 100644
--- a/google/cloud/pubsub/internal/non_constructible.h
+++ b/google/cloud/pubsub/internal/non_constructible.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A type that is not constructible.
@@ -36,7 +36,7 @@ struct NonConstructible {
   NonConstructible(NonConstructible&&) = delete;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/ordering_key_publisher_connection.cc b/google/cloud/pubsub/internal/ordering_key_publisher_connection.cc
index 608fac302e0d2..0de57afcc24be 100644
--- a/google/cloud/pubsub/internal/ordering_key_publisher_connection.cc
+++ b/google/cloud/pubsub/internal/ordering_key_publisher_connection.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 future<StatusOr<std::string>> OrderingKeyPublisherConnection::Publish(
     PublishParams p) {
@@ -51,7 +51,7 @@ OrderingKeyPublisherConnection::GetChild(std::string const& ordering_key) {
   return i.first->second;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/ordering_key_publisher_connection.h b/google/cloud/pubsub/internal/ordering_key_publisher_connection.h
index d4913eb0cfde6..220c5739ad9d3 100644
--- a/google/cloud/pubsub/internal/ordering_key_publisher_connection.h
+++ b/google/cloud/pubsub/internal/ordering_key_publisher_connection.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class OrderingKeyPublisherConnection : public pubsub::PublisherConnection {
  public:
@@ -56,7 +56,7 @@ class OrderingKeyPublisherConnection : public pubsub::PublisherConnection {
   std::map<std::string, std::shared_ptr<PublisherConnection>> children_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/ordering_key_publisher_connection_test.cc b/google/cloud/pubsub/internal/ordering_key_publisher_connection_test.cc
index d4e8610946493..a1299c5154d32 100644
--- a/google/cloud/pubsub/internal/ordering_key_publisher_connection_test.cc
+++ b/google/cloud/pubsub/internal/ordering_key_publisher_connection_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(OrderingKeyPublisherConnectionTest, Publish) {
@@ -76,7 +76,7 @@ TEST(OrderingKeyPublisherConnectionTest, Publish) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_auth.cc b/google/cloud/pubsub/internal/publisher_auth.cc
index 8f2ce3c033691..e74f672240956 100644
--- a/google/cloud/pubsub/internal/publisher_auth.cc
+++ b/google/cloud/pubsub/internal/publisher_auth.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<google::pubsub::v1::Topic> PublisherAuth::CreateTopic(
     grpc::ClientContext& context, google::pubsub::v1::Topic const& request) {
@@ -104,7 +104,7 @@ PublisherAuth::AsyncPublish(google::cloud::CompletionQueue& cq,
       });
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_auth.h b/google/cloud/pubsub/internal/publisher_auth.h
index 0f64172a68d99..0344d3c3cf522 100644
--- a/google/cloud/pubsub/internal/publisher_auth.h
+++ b/google/cloud/pubsub/internal/publisher_auth.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class PublisherAuth : public PublisherStub {
  public:
@@ -76,7 +76,7 @@ class PublisherAuth : public PublisherStub {
   std::shared_ptr<PublisherStub> child_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_auth_test.cc b/google/cloud/pubsub/internal/publisher_auth_test.cc
index 69568eba03872..d62f24784c4bf 100644
--- a/google/cloud/pubsub/internal/publisher_auth_test.cc
+++ b/google/cloud/pubsub/internal/publisher_auth_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::pubsub_testing::MockPublisherStub;
@@ -190,7 +190,7 @@ TEST(PublisherAuthTest, AsyncPublish) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_logging.cc b/google/cloud/pubsub/internal/publisher_logging.cc
index 41ae4231ee4e1..a4d692f31d892 100644
--- a/google/cloud/pubsub/internal/publisher_logging.cc
+++ b/google/cloud/pubsub/internal/publisher_logging.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::LogWrapper;
 
@@ -126,7 +126,7 @@ PublisherLogging::AsyncPublish(
       cq, std::move(context), request, __func__, tracing_options_);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_logging.h b/google/cloud/pubsub/internal/publisher_logging.h
index 3be9c98679d08..75af452da1957 100644
--- a/google/cloud/pubsub/internal/publisher_logging.h
+++ b/google/cloud/pubsub/internal/publisher_logging.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class PublisherLogging : public PublisherStub {
  public:
@@ -76,7 +76,7 @@ class PublisherLogging : public PublisherStub {
   TracingOptions tracing_options_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_logging_test.cc b/google/cloud/pubsub/internal/publisher_logging_test.cc
index 5ccccef4bacb2..4dc387eb748be 100644
--- a/google/cloud/pubsub/internal/publisher_logging_test.cc
+++ b/google/cloud/pubsub/internal/publisher_logging_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::AllOf;
@@ -179,7 +179,7 @@ TEST_F(PublisherLoggingTest, AsyncPublish) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_metadata.cc b/google/cloud/pubsub/internal/publisher_metadata.cc
index 82ce45b897a3a..f4bdead23e833 100644
--- a/google/cloud/pubsub/internal/publisher_metadata.cc
+++ b/google/cloud/pubsub/internal/publisher_metadata.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 PublisherMetadata::PublisherMetadata(std::shared_ptr<PublisherStub> child)
     : child_(std::move(child)),
@@ -97,7 +97,7 @@ void PublisherMetadata::SetMetadata(grpc::ClientContext& context,
   context.AddMetadata("x-goog-api-client", x_goog_api_client_);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_metadata.h b/google/cloud/pubsub/internal/publisher_metadata.h
index eaafea0b58cb7..3c07b8438505e 100644
--- a/google/cloud/pubsub/internal/publisher_metadata.h
+++ b/google/cloud/pubsub/internal/publisher_metadata.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class PublisherMetadata : public PublisherStub {
  public:
@@ -77,7 +77,7 @@ class PublisherMetadata : public PublisherStub {
   std::string x_goog_api_client_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_metadata_test.cc b/google/cloud/pubsub/internal/publisher_metadata_test.cc
index 04c9d6ba72bc5..0f98db1768ec5 100644
--- a/google/cloud/pubsub/internal/publisher_metadata_test.cc
+++ b/google/cloud/pubsub/internal/publisher_metadata_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsContextMDValid;
@@ -201,7 +201,7 @@ TEST(PublisherMetadataTest, AsyncPublish) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_round_robin.cc b/google/cloud/pubsub/internal/publisher_round_robin.cc
index e0038874fa1af..8f3e51bea0e71 100644
--- a/google/cloud/pubsub/internal/publisher_round_robin.cc
+++ b/google/cloud/pubsub/internal/publisher_round_robin.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<google::pubsub::v1::Topic> PublisherRoundRobin::CreateTopic(
     grpc::ClientContext& context, google::pubsub::v1::Topic const& request) {
@@ -85,7 +85,7 @@ std::shared_ptr<PublisherStub> PublisherRoundRobin::Child() {
   return child;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_round_robin.h b/google/cloud/pubsub/internal/publisher_round_robin.h
index 4269028bd88c0..ac5dbb3084891 100644
--- a/google/cloud/pubsub/internal/publisher_round_robin.h
+++ b/google/cloud/pubsub/internal/publisher_round_robin.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class PublisherRoundRobin : public PublisherStub {
  public:
@@ -79,7 +79,7 @@ class PublisherRoundRobin : public PublisherStub {
   std::size_t current_ = 0;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_round_robin_test.cc b/google/cloud/pubsub/internal/publisher_round_robin_test.cc
index 16196dc32ab46..dc40aa95af412 100644
--- a/google/cloud/pubsub/internal/publisher_round_robin_test.cc
+++ b/google/cloud/pubsub/internal/publisher_round_robin_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::InSequence;
@@ -228,7 +228,7 @@ TEST(PublisherRoundRobinTest, AsyncPublish) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_stub.cc b/google/cloud/pubsub/internal/publisher_stub.cc
index a4c8a092f5991..66865205808da 100644
--- a/google/cloud/pubsub/internal/publisher_stub.cc
+++ b/google/cloud/pubsub/internal/publisher_stub.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class DefaultPublisherStub : public PublisherStub {
  public:
@@ -134,7 +134,7 @@ std::shared_ptr<PublisherStub> CreateDefaultPublisherStub(
       google::pubsub::v1::Publisher::NewStub(std::move(channel)));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/publisher_stub.h b/google/cloud/pubsub/internal/publisher_stub.h
index 6353755fa394f..1a053f58c3404 100644
--- a/google/cloud/pubsub/internal/publisher_stub.h
+++ b/google/cloud/pubsub/internal/publisher_stub.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Define the interface for the gRPC wrapper.
@@ -105,7 +105,7 @@ std::shared_ptr<PublisherStub> CreateDefaultPublisherStub(Options const& opts,
 std::shared_ptr<PublisherStub> CreateDefaultPublisherStub(
     std::shared_ptr<grpc::Channel> channel);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/rejects_with_ordering_key.cc b/google/cloud/pubsub/internal/rejects_with_ordering_key.cc
index 901ffdc93aa9b..d26e1c145b92d 100644
--- a/google/cloud/pubsub/internal/rejects_with_ordering_key.cc
+++ b/google/cloud/pubsub/internal/rejects_with_ordering_key.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 future<StatusOr<std::string>> RejectsWithOrderingKey::Publish(PublishParams p) {
   if (!p.message.ordering_key().empty()) {
@@ -38,7 +38,7 @@ void RejectsWithOrderingKey::ResumePublish(ResumePublishParams p) {
   connection_->ResumePublish(std::move(p));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/rejects_with_ordering_key.h b/google/cloud/pubsub/internal/rejects_with_ordering_key.h
index 16466f2d0c346..a905f2d3a9aed 100644
--- a/google/cloud/pubsub/internal/rejects_with_ordering_key.h
+++ b/google/cloud/pubsub/internal/rejects_with_ordering_key.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class RejectsWithOrderingKey : public pubsub::PublisherConnection {
  public:
@@ -46,7 +46,7 @@ class RejectsWithOrderingKey : public pubsub::PublisherConnection {
   std::shared_ptr<PublisherConnection> connection_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/rejects_with_ordering_key_test.cc b/google/cloud/pubsub/internal/rejects_with_ordering_key_test.cc
index a0ac6cc4e6ea2..f666837bcd2fd 100644
--- a/google/cloud/pubsub/internal/rejects_with_ordering_key_test.cc
+++ b/google/cloud/pubsub/internal/rejects_with_ordering_key_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -59,7 +59,7 @@ TEST(RejectsWithOrderingKeyTest, MessageAccepted) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_auth.cc b/google/cloud/pubsub/internal/schema_auth.cc
index 7e6e816563dcb..53eb7fee14c8f 100644
--- a/google/cloud/pubsub/internal/schema_auth.cc
+++ b/google/cloud/pubsub/internal/schema_auth.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<google::pubsub::v1::Schema> SchemaAuth::CreateSchema(
     grpc::ClientContext& context,
@@ -69,7 +69,7 @@ SchemaAuth::ValidateMessage(
   return child_->ValidateMessage(context, request);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_auth.h b/google/cloud/pubsub/internal/schema_auth.h
index 7339a93380cc5..2b1723f89fb2b 100644
--- a/google/cloud/pubsub/internal/schema_auth.h
+++ b/google/cloud/pubsub/internal/schema_auth.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A Decorator for `SchemaStub` that logs each request and response.
@@ -59,7 +59,7 @@ class SchemaAuth : public SchemaStub {
   std::shared_ptr<SchemaStub> child_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_auth_test.cc b/google/cloud/pubsub/internal/schema_auth_test.cc
index 11cc3291429c5..0508e00a2ad98 100644
--- a/google/cloud/pubsub/internal/schema_auth_test.cc
+++ b/google/cloud/pubsub/internal/schema_auth_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::MakeTypicalMockAuth;
@@ -128,7 +128,7 @@ TEST(SchemaAuthTest, ValidateMessage) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_logging.cc b/google/cloud/pubsub/internal/schema_logging.cc
index e4e1a187a3cfe..16afaeeeb5118 100644
--- a/google/cloud/pubsub/internal/schema_logging.cc
+++ b/google/cloud/pubsub/internal/schema_logging.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::LogWrapper;
 
@@ -90,7 +90,7 @@ SchemaLogging::ValidateMessage(
       context, request, __func__, tracing_options_);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_logging.h b/google/cloud/pubsub/internal/schema_logging.h
index 832515a548e5e..3a64b6f3e2cab 100644
--- a/google/cloud/pubsub/internal/schema_logging.h
+++ b/google/cloud/pubsub/internal/schema_logging.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A Decorator for `SchemaStub` that logs each request and response.
@@ -59,7 +59,7 @@ class SchemaLogging : public SchemaStub {
   TracingOptions tracing_options_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_logging_test.cc b/google/cloud/pubsub/internal/schema_logging_test.cc
index 1e7c6047cf82c..d26c4e3aec885 100644
--- a/google/cloud/pubsub/internal/schema_logging_test.cc
+++ b/google/cloud/pubsub/internal/schema_logging_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -113,7 +113,7 @@ TEST_F(SchemaLoggingTest, ValidateMessage) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_metadata.cc b/google/cloud/pubsub/internal/schema_metadata.cc
index 428ceefa784ee..11269f8b9bf17 100644
--- a/google/cloud/pubsub/internal/schema_metadata.cc
+++ b/google/cloud/pubsub/internal/schema_metadata.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 SchemaMetadata::SchemaMetadata(std::shared_ptr<SchemaStub> child)
     : child_(std::move(child)),
@@ -74,7 +74,7 @@ void SchemaMetadata::SetMetadata(grpc::ClientContext& context,
   context.AddMetadata("x-goog-api-client", x_goog_api_client_);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_metadata.h b/google/cloud/pubsub/internal/schema_metadata.h
index 0e84ca73740b5..1e3f1171b8210 100644
--- a/google/cloud/pubsub/internal/schema_metadata.h
+++ b/google/cloud/pubsub/internal/schema_metadata.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A Decorator for `SchemaStub` that logs each request and response.
@@ -59,7 +59,7 @@ class SchemaMetadata : public SchemaStub {
   std::string x_goog_api_client_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_metadata_test.cc b/google/cloud/pubsub/internal/schema_metadata_test.cc
index 2f4f80062bcd8..fba81d62e012b 100644
--- a/google/cloud/pubsub/internal/schema_metadata_test.cc
+++ b/google/cloud/pubsub/internal/schema_metadata_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::pubsub::Schema;
@@ -148,7 +148,7 @@ TEST(SchemaMetadataTest, ValidateMessage) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_stub.cc b/google/cloud/pubsub/internal/schema_stub.cc
index 8fead3db06b5b..17312684c0a6d 100644
--- a/google/cloud/pubsub/internal/schema_stub.cc
+++ b/google/cloud/pubsub/internal/schema_stub.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class DefaultSchemaStub : public SchemaStub {
@@ -96,7 +96,7 @@ std::shared_ptr<SchemaStub> CreateDefaultSchemaStub(
       google::pubsub::v1::SchemaService::NewStub(std::move(channel)));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/schema_stub.h b/google/cloud/pubsub/internal/schema_stub.h
index faa6c63368431..15ae33ca72f79 100644
--- a/google/cloud/pubsub/internal/schema_stub.h
+++ b/google/cloud/pubsub/internal/schema_stub.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Define the interface for the gRPC wrapper.
@@ -76,7 +76,7 @@ class SchemaStub {
 std::shared_ptr<SchemaStub> CreateDefaultSchemaStub(
     std::shared_ptr<grpc::Channel> channel);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/sequential_batch_sink.cc b/google/cloud/pubsub/internal/sequential_batch_sink.cc
index c60d80b2ec887..166df630e4987 100644
--- a/google/cloud/pubsub/internal/sequential_batch_sink.cc
+++ b/google/cloud/pubsub/internal/sequential_batch_sink.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 SequentialBatchSink::SequentialBatchSink(
     std::shared_ptr<pubsub_internal::BatchSink> sink)
@@ -96,7 +96,7 @@ void SequentialBatchSink::OnPublish(Status s) {
       .then(MoveCaptureRequest{WeakFromThis(), std::move(pr.promise)});
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/sequential_batch_sink.h b/google/cloud/pubsub/internal/sequential_batch_sink.h
index 738cb065e0a5e..95fbe47ce44e4 100644
--- a/google/cloud/pubsub/internal/sequential_batch_sink.h
+++ b/google/cloud/pubsub/internal/sequential_batch_sink.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Publish message batches using a stub, with retries, but no queueing.
 class SequentialBatchSink
@@ -74,7 +74,7 @@ class SequentialBatchSink
   Status corked_on_error_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/sequential_batch_sink_test.cc b/google/cloud/pubsub/internal/sequential_batch_sink_test.cc
index f63a3a8c1c32d..66ca8bcd1cffb 100644
--- a/google/cloud/pubsub/internal/sequential_batch_sink_test.cc
+++ b/google/cloud/pubsub/internal/sequential_batch_sink_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::AsyncSequencer;
@@ -176,7 +176,7 @@ TEST(DefaultBatchSinkTest, BasicErrorHandling) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/session_shutdown_manager.cc b/google/cloud/pubsub/internal/session_shutdown_manager.cc
index 09db73ec707b4..1c9752460f8de 100644
--- a/google/cloud/pubsub/internal/session_shutdown_manager.cc
+++ b/google/cloud/pubsub/internal/session_shutdown_manager.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string FormatOps(std::unordered_map<std::string, int> const& ops) {
   std::ostringstream os;
@@ -89,7 +89,7 @@ void SessionShutdownManager::SignalOnShutdown(std::unique_lock<std::mutex> lk) {
   p.set_value(std::move(s));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/session_shutdown_manager.h b/google/cloud/pubsub/internal/session_shutdown_manager.h
index 195d45089e8c9..2f1ef0390895d 100644
--- a/google/cloud/pubsub/internal/session_shutdown_manager.h
+++ b/google/cloud/pubsub/internal/session_shutdown_manager.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A helper class to track (and debug) `SubscriptionSession`'s shutdown process
@@ -122,7 +122,7 @@ class SessionShutdownManager {
   std::unordered_map<std::string, int> ops_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/session_shutdown_manager_test.cc b/google/cloud/pubsub/internal/session_shutdown_manager_test.cc
index 554fb278bcc3c..e534ab71327f2 100644
--- a/google/cloud/pubsub/internal/session_shutdown_manager_test.cc
+++ b/google/cloud/pubsub/internal/session_shutdown_manager_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 /// @test Verify SessionShutdownManager works correctly.
@@ -60,7 +60,7 @@ TEST(SessionShutdownManagerTest, Basic) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/streaming_subscription_batch_source.cc b/google/cloud/pubsub/internal/streaming_subscription_batch_source.cc
index 8581963e0ca63..22667c46914ea 100644
--- a/google/cloud/pubsub/internal/streaming_subscription_batch_source.cc
+++ b/google/cloud/pubsub/internal/streaming_subscription_batch_source.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 void StreamingSubscriptionBatchSource::Start(BatchCallback callback) {
   std::unique_lock<std::mutex> lk(mu_);
@@ -390,7 +390,7 @@ void StreamingSubscriptionBatchSource::ChangeState(
   stream_state_ = s;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/streaming_subscription_batch_source.h b/google/cloud/pubsub/internal/streaming_subscription_batch_source.h
index 9adb838906420..7dde573962346 100644
--- a/google/cloud/pubsub/internal/streaming_subscription_batch_source.h
+++ b/google/cloud/pubsub/internal/streaming_subscription_batch_source.h
@@ -36,7 +36,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Configuration parameters to batch Ack/Nack responses.
@@ -174,7 +174,7 @@ class StreamingSubscriptionBatchSource
 std::ostream& operator<<(std::ostream& os,
                          StreamingSubscriptionBatchSource::StreamState s);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/streaming_subscription_batch_source_test.cc b/google/cloud/pubsub/internal/streaming_subscription_batch_source_test.cc
index b37650bf69d3a..15333d4b21c00 100644
--- a/google/cloud/pubsub/internal/streaming_subscription_batch_source_test.cc
+++ b/google/cloud/pubsub/internal/streaming_subscription_batch_source_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::AutomaticallyCreatedBackgroundThreads;
@@ -805,7 +805,7 @@ TEST(StreamingSubscriptionBatchSourceTest, StateOStream) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_auth.cc b/google/cloud/pubsub/internal/subscriber_auth.cc
index 0de5385f4ca86..9cd4e6a23b675 100644
--- a/google/cloud/pubsub/internal/subscriber_auth.cc
+++ b/google/cloud/pubsub/internal/subscriber_auth.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<google::pubsub::v1::Subscription> SubscriberAuth::CreateSubscription(
     grpc::ClientContext& context,
@@ -162,7 +162,7 @@ StatusOr<google::pubsub::v1::SeekResponse> SubscriberAuth::Seek(
   return child_->Seek(context, request);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_auth.h b/google/cloud/pubsub/internal/subscriber_auth.h
index 26c786619db00..78265bc8d7a66 100644
--- a/google/cloud/pubsub/internal/subscriber_auth.h
+++ b/google/cloud/pubsub/internal/subscriber_auth.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class SubscriberAuth : public SubscriberStub {
  public:
@@ -100,7 +100,7 @@ class SubscriberAuth : public SubscriberStub {
   std::shared_ptr<SubscriberStub> child_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_auth_test.cc b/google/cloud/pubsub/internal/subscriber_auth_test.cc
index 878b65c0b7149..fe73a6bd567d2 100644
--- a/google/cloud/pubsub/internal/subscriber_auth_test.cc
+++ b/google/cloud/pubsub/internal/subscriber_auth_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::MakeTypicalAsyncMockAuth;
@@ -289,7 +289,7 @@ TEST(SubscriberAuthTest, Seek) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_logging.cc b/google/cloud/pubsub/internal/subscriber_logging.cc
index 32fe4895c00ca..321e6a176bcfd 100644
--- a/google/cloud/pubsub/internal/subscriber_logging.cc
+++ b/google/cloud/pubsub/internal/subscriber_logging.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::DebugString;
 using ::google::cloud::internal::LogWrapper;
@@ -282,7 +282,7 @@ future<Status> LoggingAsyncPullStream::Finish() {
   });
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_logging.h b/google/cloud/pubsub/internal/subscriber_logging.h
index 2e635a5db8e7e..106faf4acc6f6 100644
--- a/google/cloud/pubsub/internal/subscriber_logging.h
+++ b/google/cloud/pubsub/internal/subscriber_logging.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class SubscriberLogging : public SubscriberStub {
  public:
@@ -124,7 +124,7 @@ class LoggingAsyncPullStream : public SubscriberStub::AsyncPullStream {
   std::string request_id_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_logging_test.cc b/google/cloud/pubsub/internal/subscriber_logging_test.cc
index b0bdcbca11b78..ea9d01f3adfa8 100644
--- a/google/cloud/pubsub/internal/subscriber_logging_test.cc
+++ b/google/cloud/pubsub/internal/subscriber_logging_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::AllOf;
@@ -322,7 +322,7 @@ TEST_F(SubscriberLoggingTest, Seek) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_metadata.cc b/google/cloud/pubsub/internal/subscriber_metadata.cc
index 78a8993fbcc0d..7c335d4a4464f 100644
--- a/google/cloud/pubsub/internal/subscriber_metadata.cc
+++ b/google/cloud/pubsub/internal/subscriber_metadata.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 SubscriberMetadata::SubscriberMetadata(std::shared_ptr<SubscriberStub> child)
     : child_(std::move(child)),
@@ -144,7 +144,7 @@ void SubscriberMetadata::SetMetadata(grpc::ClientContext& context,
   context.AddMetadata("x-goog-api-client", x_goog_api_client_);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_metadata.h b/google/cloud/pubsub/internal/subscriber_metadata.h
index 9b8197d8b1335..2a510598b9f63 100644
--- a/google/cloud/pubsub/internal/subscriber_metadata.h
+++ b/google/cloud/pubsub/internal/subscriber_metadata.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class SubscriberMetadata : public SubscriberStub {
  public:
@@ -101,7 +101,7 @@ class SubscriberMetadata : public SubscriberStub {
   std::string x_goog_api_client_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_metadata_test.cc b/google/cloud/pubsub/internal/subscriber_metadata_test.cc
index e3fbae6db95fb..38087cd24ab67 100644
--- a/google/cloud/pubsub/internal/subscriber_metadata_test.cc
+++ b/google/cloud/pubsub/internal/subscriber_metadata_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsContextMDValid;
@@ -320,7 +320,7 @@ TEST(SubscriberMetadataTest, Seek) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_round_robin.cc b/google/cloud/pubsub/internal/subscriber_round_robin.cc
index cffeabea0db76..2ecab08f786ff 100644
--- a/google/cloud/pubsub/internal/subscriber_round_robin.cc
+++ b/google/cloud/pubsub/internal/subscriber_round_robin.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<google::pubsub::v1::Subscription>
 SubscriberRoundRobin::CreateSubscription(
@@ -125,7 +125,7 @@ std::shared_ptr<SubscriberStub> SubscriberRoundRobin::Child() {
   return child;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_round_robin.h b/google/cloud/pubsub/internal/subscriber_round_robin.h
index 13a8dd6135fc1..055eb918de1c0 100644
--- a/google/cloud/pubsub/internal/subscriber_round_robin.h
+++ b/google/cloud/pubsub/internal/subscriber_round_robin.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class SubscriberRoundRobin : public SubscriberStub {
  public:
@@ -103,7 +103,7 @@ class SubscriberRoundRobin : public SubscriberStub {
   std::size_t current_ = 0;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_round_robin_test.cc b/google/cloud/pubsub/internal/subscriber_round_robin_test.cc
index c66f04f87aa5e..edcdfafcfde6b 100644
--- a/google/cloud/pubsub/internal/subscriber_round_robin_test.cc
+++ b/google/cloud/pubsub/internal/subscriber_round_robin_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::InSequence;
@@ -337,7 +337,7 @@ TEST(SubscriberRoundRobinTest, Seek) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_stub.cc b/google/cloud/pubsub/internal/subscriber_stub.cc
index 3b0f0c0c5d199..ede9b102a6843 100644
--- a/google/cloud/pubsub/internal/subscriber_stub.cc
+++ b/google/cloud/pubsub/internal/subscriber_stub.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class DefaultSubscriberStub : public SubscriberStub {
  public:
@@ -205,7 +205,7 @@ std::shared_ptr<SubscriberStub> CreateDefaultSubscriberStub(Options const& opts,
   return CreateDefaultSubscriberStub(CreateChannel(opts, channel_id));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscriber_stub.h b/google/cloud/pubsub/internal/subscriber_stub.h
index 86f874f58e49d..2a76cb0b3e53e 100644
--- a/google/cloud/pubsub/internal/subscriber_stub.h
+++ b/google/cloud/pubsub/internal/subscriber_stub.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Define the interface for the gRPC wrapper.
@@ -136,7 +136,7 @@ std::shared_ptr<SubscriberStub> CreateDefaultSubscriberStub(
 std::shared_ptr<SubscriberStub> CreateDefaultSubscriberStub(Options const& opts,
                                                             int channel_id);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_batch_source.h b/google/cloud/pubsub/internal/subscription_batch_source.h
index ea0391d01c1d2..508fa181d1a4d 100644
--- a/google/cloud/pubsub/internal/subscription_batch_source.h
+++ b/google/cloud/pubsub/internal/subscription_batch_source.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using BatchCallback =
     std::function<void(StatusOr<google::pubsub::v1::StreamingPullResponse>)>;
@@ -83,7 +83,7 @@ class SubscriptionBatchSource {
                             std::chrono::seconds extension) = 0;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_concurrency_control.cc b/google/cloud/pubsub/internal/subscription_concurrency_control.cc
index 7a40bc772bb35..3cd095c92598a 100644
--- a/google/cloud/pubsub/internal/subscription_concurrency_control.cc
+++ b/google/cloud/pubsub/internal/subscription_concurrency_control.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 class AckHandlerImpl : public pubsub::AckHandler::Impl {
  public:
@@ -118,7 +118,7 @@ void SubscriptionConcurrencyControl::OnMessageAsync(
   shutdown_manager_->FinishedOperation("callback");
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_concurrency_control.h b/google/cloud/pubsub/internal/subscription_concurrency_control.h
index ef9746416513f..a487954cbda9c 100644
--- a/google/cloud/pubsub/internal/subscription_concurrency_control.h
+++ b/google/cloud/pubsub/internal/subscription_concurrency_control.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class SubscriptionConcurrencyControl
     : public std::enable_shared_from_this<SubscriptionConcurrencyControl> {
@@ -78,7 +78,7 @@ class SubscriptionConcurrencyControl
   std::size_t messages_requested_ = 0;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_concurrency_control_test.cc b/google/cloud/pubsub/internal/subscription_concurrency_control_test.cc
index 27d4bbf33b3ba..35ac91515eb94 100644
--- a/google/cloud/pubsub/internal/subscription_concurrency_control_test.cc
+++ b/google/cloud/pubsub/internal/subscription_concurrency_control_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -503,7 +503,7 @@ TEST_F(SubscriptionConcurrencyControlTest, MessageContents) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_lease_management.cc b/google/cloud/pubsub/internal/subscription_lease_management.cc
index efed260ae6025..006701e2219d5 100644
--- a/google/cloud/pubsub/internal/subscription_lease_management.cc
+++ b/google/cloud/pubsub/internal/subscription_lease_management.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::chrono::seconds constexpr SubscriptionLeaseManagement::kMinimumAckDeadline;
 std::chrono::seconds constexpr SubscriptionLeaseManagement::kAckDeadlineSlack;
@@ -161,7 +161,7 @@ void SubscriptionLeaseManagement::NackAll(std::unique_lock<std::mutex> lk) {
   BulkNack(std::move(ack_ids));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_lease_management.h b/google/cloud/pubsub/internal/subscription_lease_management.h
index e63db520beaa6..25e388027767d 100644
--- a/google/cloud/pubsub/internal/subscription_lease_management.h
+++ b/google/cloud/pubsub/internal/subscription_lease_management.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class SubscriptionLeaseManagement
     : public SubscriptionBatchSource,
@@ -105,7 +105,7 @@ class SubscriptionLeaseManagement
   future<void> refresh_timer_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_lease_management_test.cc b/google/cloud/pubsub/internal/subscription_lease_management_test.cc
index af08642fed300..8e602a98b1f64 100644
--- a/google/cloud/pubsub/internal/subscription_lease_management_test.cc
+++ b/google/cloud/pubsub/internal/subscription_lease_management_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::FakeCompletionQueueImpl;
@@ -213,7 +213,7 @@ TEST(SubscriptionLeaseManagementTest, UsesDeadlineExtension) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_message_queue.cc b/google/cloud/pubsub/internal/subscription_message_queue.cc
index 178919b30255a..c63777e961f6c 100644
--- a/google/cloud/pubsub/internal/subscription_message_queue.cc
+++ b/google/cloud/pubsub/internal/subscription_message_queue.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 void SubscriptionMessageQueue::Start(MessageCallback cb) {
   std::unique_lock<std::mutex> lk(mu_);
@@ -173,7 +173,7 @@ void SubscriptionMessageQueue::HandlerDone(std::string const& ack_id) {
   DrainQueue(std::move(lk));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_message_queue.h b/google/cloud/pubsub/internal/subscription_message_queue.h
index 1a693667526d4..f643a43dc5563 100644
--- a/google/cloud/pubsub/internal/subscription_message_queue.h
+++ b/google/cloud/pubsub/internal/subscription_message_queue.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Keeps the queue of runnable messages.
@@ -107,7 +107,7 @@ class SubscriptionMessageQueue
   absl::flat_hash_map<std::string, std::string> ordering_key_by_ack_id_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_message_queue_test.cc b/google/cloud/pubsub/internal/subscription_message_queue_test.cc
index f651055a020f1..d814eb935a0af 100644
--- a/google/cloud/pubsub/internal/subscription_message_queue_test.cc
+++ b/google/cloud/pubsub/internal/subscription_message_queue_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -511,7 +511,7 @@ INSTANTIATE_TEST_SUITE_P(
     ::testing::PrintToStringParamName());
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_message_source.h b/google/cloud/pubsub/internal/subscription_message_source.h
index 084607f9f3289..ae26b7f27a902 100644
--- a/google/cloud/pubsub/internal/subscription_message_source.h
+++ b/google/cloud/pubsub/internal/subscription_message_source.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using MessageCallback =
     std::function<void(google::pubsub::v1::ReceivedMessage)>;
@@ -70,7 +70,7 @@ class SubscriptionMessageSource {
   virtual void NackMessage(std::string const& ack_id) = 0;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_session.cc b/google/cloud/pubsub/internal/subscription_session.cc
index 366b52d7661c8..7e7a6bc8c44ea 100644
--- a/google/cloud/pubsub/internal/subscription_session.cc
+++ b/google/cloud/pubsub/internal/subscription_session.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class SubscriptionSessionImpl
@@ -175,7 +175,7 @@ future<Status> CreateSubscriptionSession(
                                          std::move(p));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_session.h b/google/cloud/pubsub/internal/subscription_session.h
index 8ffe3fc6cdb74..042e42a6fd243 100644
--- a/google/cloud/pubsub/internal/subscription_session.h
+++ b/google/cloud/pubsub/internal/subscription_session.h
@@ -32,14 +32,14 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 future<Status> CreateSubscriptionSession(
     pubsub::Subscription const& subscription, Options const& opts,
     std::shared_ptr<SubscriberStub> const& stub, CompletionQueue const& cq,
     std::string client_id, pubsub::SubscriberConnection::SubscribeParams p);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/internal/subscription_session_test.cc b/google/cloud/pubsub/internal/subscription_session_test.cc
index b025b9e00dd3a..5d93ad79befd9 100644
--- a/google/cloud/pubsub/internal/subscription_session_test.cc
+++ b/google/cloud/pubsub/internal/subscription_session_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::pubsub_testing::FakeAsyncStreamingPull;
@@ -631,7 +631,7 @@ TEST(SubscriptionSessionTest, FireAndForgetShutdown) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/message.cc b/google/cloud/pubsub/message.cc
index 9bebe9aecf41f..1dd08d4b8350a 100644
--- a/google/cloud/pubsub/message.cc
+++ b/google/cloud/pubsub/message.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::size_t MessageProtoSize(::google::pubsub::v1::PubsubMessage const& m) {
   // see https://cloud.google.com/pubsub/pricing
   auto constexpr kTimestampOverhead = 20;
@@ -33,11 +33,11 @@ std::size_t MessageProtoSize(::google::pubsub::v1::PubsubMessage const& m) {
   }
   return s;
 }
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::chrono::system_clock::time_point Message::publish_time() const {
   return google::cloud::internal::ToChronoTimePoint(proto_.publish_time());
@@ -62,7 +62,7 @@ std::ostream& operator<<(std::ostream& os, Message const& rhs) {
   return os << text;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/message.h b/google/cloud/pubsub/message.h
index 0d6ed7a3da61e..ff10a83371627 100644
--- a/google/cloud/pubsub/message.h
+++ b/google/cloud/pubsub/message.h
@@ -26,24 +26,24 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class Message;
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 ::google::pubsub::v1::PubsubMessage const& ToProto(pubsub::Message const&);
 ::google::pubsub::v1::PubsubMessage&& ToProto(pubsub::Message&&);
 pubsub::Message FromProto(::google::pubsub::v1::PubsubMessage);
 
 /// Estimate the size of a message.
 std::size_t MessageSize(pubsub::Message const&);
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class MessageBuilder;
 
 /**
@@ -261,11 +261,11 @@ class MessageBuilder {
   google::pubsub::v1::PubsubMessage proto_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 inline ::google::pubsub::v1::PubsubMessage const& ToProto(
     pubsub::Message const& m) {
   return m.proto_;
@@ -285,7 +285,7 @@ inline std::size_t MessageSize(pubsub::Message const& m) {
 
 std::size_t MessageProtoSize(::google::pubsub::v1::PubsubMessage const& m);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/message_test.cc b/google/cloud/pubsub/message_test.cc
index 40449cc063bdc..a35fa8fde1896 100644
--- a/google/cloud/pubsub/message_test.cc
+++ b/google/cloud/pubsub/message_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -262,7 +262,7 @@ TEST(Message, SizeEstimation) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/mocks/mock_ack_handler.h b/google/cloud/pubsub/mocks/mock_ack_handler.h
index a9fbd84759bac..1caf625acb80d 100644
--- a/google/cloud/pubsub/mocks/mock_ack_handler.h
+++ b/google/cloud/pubsub/mocks/mock_ack_handler.h
@@ -32,7 +32,7 @@ namespace pubsub_mocks {
  * `pubsub::Foo` in their source, but the symbols are versioned, i.e., the
  * symbol becomes `pubsub::v1::Foo`.
  */
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A googlemock-based mock for [pubsub::AckHandler::Impl][mocked-link]
@@ -49,7 +49,7 @@ class MockAckHandler : public pubsub::AckHandler::Impl {
   MOCK_METHOD(std::int32_t, delivery_attempt, (), (const, override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_mocks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/mocks/mock_publisher_connection.h b/google/cloud/pubsub/mocks/mock_publisher_connection.h
index e6711d25b1e6d..982906c5712d3 100644
--- a/google/cloud/pubsub/mocks/mock_publisher_connection.h
+++ b/google/cloud/pubsub/mocks/mock_publisher_connection.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_mocks {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A googlemock-based mock for [pubsub::PublisherConnection][mocked-link]
@@ -41,7 +41,7 @@ class MockPublisherConnection : public pubsub::PublisherConnection {
               (pubsub::PublisherConnection::ResumePublishParams), (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_mocks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/mocks/mock_schema_admin_connection.h b/google/cloud/pubsub/mocks/mock_schema_admin_connection.h
index 7d66e40e2c425..26c64a1a7ae53 100644
--- a/google/cloud/pubsub/mocks/mock_schema_admin_connection.h
+++ b/google/cloud/pubsub/mocks/mock_schema_admin_connection.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A googlemock-based mock for
@@ -53,7 +53,7 @@ class MockSchemaAdminConnection : public pubsub::SchemaAdminConnection {
               (google::pubsub::v1::ValidateMessageRequest const&), (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/mocks/mock_subscriber_connection.h b/google/cloud/pubsub/mocks/mock_subscriber_connection.h
index bb12b295bbf2a..587a64c3f4157 100644
--- a/google/cloud/pubsub/mocks/mock_subscriber_connection.h
+++ b/google/cloud/pubsub/mocks/mock_subscriber_connection.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_mocks {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A googlemock-based mock for [pubsub::SubscriberConnection][mocked-link]
@@ -36,7 +36,7 @@ class MockSubscriberConnection : public pubsub::SubscriberConnection {
               (pubsub::SubscriberConnection::SubscribeParams), (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_mocks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/mocks/mock_subscription_admin_connection.h b/google/cloud/pubsub/mocks/mock_subscription_admin_connection.h
index efcb18af429fd..0643982bbe217 100644
--- a/google/cloud/pubsub/mocks/mock_subscription_admin_connection.h
+++ b/google/cloud/pubsub/mocks/mock_subscription_admin_connection.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_mocks {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A googlemock-based mock for
@@ -67,7 +67,7 @@ class MockSubscriptionAdminConnection
               (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_mocks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/mocks/mock_topic_admin_connection.h b/google/cloud/pubsub/mocks/mock_topic_admin_connection.h
index 308a1b30cebd7..81fd3b75c7cd1 100644
--- a/google/cloud/pubsub/mocks/mock_topic_admin_connection.h
+++ b/google/cloud/pubsub/mocks/mock_topic_admin_connection.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_mocks {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A googlemock-based mock for [pubsub::TopicAdminConnection][mocked-link]
@@ -54,7 +54,7 @@ class MockTopicAdminConnection : public pubsub::TopicAdminConnection {
               (ListTopicSnapshotsParams), (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_mocks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/options.h b/google/cloud/pubsub/options.h
index f2d201fad3411..e3d4ccd557285 100644
--- a/google/cloud/pubsub/options.h
+++ b/google/cloud/pubsub/options.h
@@ -47,7 +47,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// The retry policy
 struct RetryPolicyOption {
@@ -284,7 +284,7 @@ using SubscriberOptionList =
                MaxOutstandingMessagesOption, MaxOutstandingBytesOption,
                MaxConcurrencyOption, ShutdownPollingPeriodOption>;
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher.cc b/google/cloud/pubsub/publisher.cc
index 122fe10101697..942dc9484627f 100644
--- a/google/cloud/pubsub/publisher.cc
+++ b/google/cloud/pubsub/publisher.cc
@@ -17,13 +17,13 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Publisher::Publisher(std::shared_ptr<PublisherConnection> connection,
                      PublisherOptions const&)
     : connection_(std::move(connection)) {}
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher.h b/google/cloud/pubsub/publisher.h
index d702a3f1851d6..2d19b2dc6f67f 100644
--- a/google/cloud/pubsub/publisher.h
+++ b/google/cloud/pubsub/publisher.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Publish messages to the Cloud Pub/Sub service.
  *
@@ -191,7 +191,7 @@ class Publisher {
   std::shared_ptr<PublisherConnection> connection_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher_connection.cc b/google/cloud/pubsub/publisher_connection.cc
index 5672ce584bd94..a1591bb54afc5 100644
--- a/google/cloud/pubsub/publisher_connection.cc
+++ b/google/cloud/pubsub/publisher_connection.cc
@@ -35,7 +35,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 class ContainingPublisherConnection : public PublisherConnection {
  public:
@@ -163,11 +163,11 @@ std::shared_ptr<PublisherConnection> MakePublisherConnection(
   return MakePublisherConnection(std::move(topic), std::move(opts));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<pubsub::PublisherConnection> MakePublisherConnection(
     pubsub::Topic topic, Options opts,
@@ -182,7 +182,7 @@ std::shared_ptr<pubsub::PublisherConnection> MakePublisherConnection(
                                              std::move(stub));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher_connection.h b/google/cloud/pubsub/publisher_connection.h
index 7d355d2d904ab..324c664f788af 100644
--- a/google/cloud/pubsub/publisher_connection.h
+++ b/google/cloud/pubsub/publisher_connection.h
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A connection to the Cloud Pub/Sub service to publish events.
@@ -158,17 +158,17 @@ std::shared_ptr<PublisherConnection> MakePublisherConnection(
     std::unique_ptr<RetryPolicy const> retry_policy = {},
     std::unique_ptr<BackoffPolicy const> backoff_policy = {});
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<pubsub::PublisherConnection> MakePublisherConnection(
     pubsub::Topic topic, Options opts,
     std::vector<std::shared_ptr<PublisherStub>> stubs);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher_connection_test.cc b/google/cloud/pubsub/publisher_connection_test.cc
index 6130e555e09db..fd3a1648fcb5a 100644
--- a/google/cloud/pubsub/publisher_connection_test.cc
+++ b/google/cloud/pubsub/publisher_connection_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::AsyncSequencer;
@@ -345,7 +345,7 @@ TEST(PublisherConnectionTest, HandleTransientEnabledRetry) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher_options.cc b/google/cloud/pubsub/publisher_options.cc
index 46c08cff89b31..75e1ff5e4c14a 100644
--- a/google/cloud/pubsub/publisher_options.cc
+++ b/google/cloud/pubsub/publisher_options.cc
@@ -18,14 +18,14 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 PublisherOptions::PublisherOptions(Options opts) {
   internal::CheckExpectedOptions<PublisherOptionList>(opts, __func__);
   opts_ = pubsub_internal::DefaultPublisherOptionsOnly(std::move(opts));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher_options.h b/google/cloud/pubsub/publisher_options.h
index 8fe71fad3a165..4d4075975accc 100644
--- a/google/cloud/pubsub/publisher_options.h
+++ b/google/cloud/pubsub/publisher_options.h
@@ -26,19 +26,19 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class PublisherOptions;
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 Options MakeOptions(pubsub::PublisherOptions);
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Configuration options for a `Publisher`.
@@ -260,17 +260,17 @@ class PublisherOptions {
   Options opts_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 inline Options MakeOptions(pubsub::PublisherOptions o) {
   return std::move(o.opts_);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher_options_test.cc b/google/cloud/pubsub/publisher_options_test.cc
index 45ea66d53d7bb..dd11f90aa7a1b 100644
--- a/google/cloud/pubsub/publisher_options_test.cc
+++ b/google/cloud/pubsub/publisher_options_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -153,7 +153,7 @@ TEST(PublisherOptions, MakeOptions) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/publisher_test.cc b/google/cloud/pubsub/publisher_test.cc
index 0013c5fd3f5a6..7c69b2b874bc5 100644
--- a/google/cloud/pubsub/publisher_test.cc
+++ b/google/cloud/pubsub/publisher_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 // Tests {copy,move}x{constructor,assignment} + equality.
@@ -64,7 +64,7 @@ TEST(PublisherTest, PublishSimple) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/retry_policy.h b/google/cloud/pubsub/retry_policy.h
index b260177321852..b57b709f948b6 100644
--- a/google/cloud/pubsub/retry_policy.h
+++ b/google/cloud/pubsub/retry_policy.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// Define the gRPC status code semantics for retrying requests.
 struct RetryTraits {
   static inline bool IsPermanentFailure(google::cloud::Status const& status) {
@@ -35,11 +35,11 @@ struct RetryTraits {
   }
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// The base class for retry policies.
 using RetryPolicy = ::google::cloud::internal::TraitBasedRetryPolicy<
@@ -55,7 +55,7 @@ using LimitedErrorCountRetryPolicy =
     google::cloud::internal::LimitedErrorCountRetryPolicy<
         pubsub_internal::RetryTraits>;
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema.cc b/google/cloud/pubsub/schema.cc
index 23fb9bea3cde4..828d01f517ce6 100644
--- a/google/cloud/pubsub/schema.cc
+++ b/google/cloud/pubsub/schema.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string Schema::FullName() const {
   return "projects/" + project_id() + "/schemas/" + schema_id();
@@ -31,7 +31,7 @@ std::ostream& operator<<(std::ostream& os, Schema const& rhs) {
   return os << rhs.FullName();
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema.h b/google/cloud/pubsub/schema.h
index 7f8246e7045d1..c29cb139a9e5b 100644
--- a/google/cloud/pubsub/schema.h
+++ b/google/cloud/pubsub/schema.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Objects of this class identify a Cloud Pub/Sub schema.
@@ -74,7 +74,7 @@ class Schema {
   std::string schema_id_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema_admin_client.cc b/google/cloud/pubsub/schema_admin_client.cc
index 649e70cf0faef..048c39115af66 100644
--- a/google/cloud/pubsub/schema_admin_client.cc
+++ b/google/cloud/pubsub/schema_admin_client.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 SchemaAdminClient::SchemaAdminClient(
     std::shared_ptr<SchemaAdminConnection> connection)
@@ -143,7 +143,7 @@ SchemaAdminClient::ValidateMessage(
   return connection_->ValidateMessage(request);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema_admin_client.h b/google/cloud/pubsub/schema_admin_client.h
index a1590affafd78..1c71ee9c3faef 100644
--- a/google/cloud/pubsub/schema_admin_client.h
+++ b/google/cloud/pubsub/schema_admin_client.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Performs schema admin operations in Cloud Pub/Sub.
@@ -244,7 +244,7 @@ class SchemaAdminClient {
   std::shared_ptr<SchemaAdminConnection> connection_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema_admin_client_test.cc b/google/cloud/pubsub/schema_admin_client_test.cc
index 0548052d872f6..9ea2292560f2f 100644
--- a/google/cloud/pubsub/schema_admin_client_test.cc
+++ b/google/cloud/pubsub/schema_admin_client_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -347,7 +347,7 @@ TEST(SchemaAdminClient, ValidateMessageWithProtobuf) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema_admin_connection.cc b/google/cloud/pubsub/schema_admin_connection.cc
index 753573403108c..208fac6b771ed 100644
--- a/google/cloud/pubsub/schema_admin_connection.cc
+++ b/google/cloud/pubsub/schema_admin_connection.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::Idempotency;
@@ -176,11 +176,11 @@ std::shared_ptr<pubsub::SchemaAdminConnection> MakeSchemaAdminConnection(
       opts.get<pubsub::BackoffPolicyOption>()->clone());
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 SchemaAdminConnection::~SchemaAdminConnection() = default;
 
@@ -219,7 +219,7 @@ std::shared_ptr<SchemaAdminConnection> MakeSchemaAdminConnection(
   return MakeSchemaAdminConnection(std::move(opts));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema_admin_connection.h b/google/cloud/pubsub/schema_admin_connection.h
index 47d8af2a4831d..2d875ae6f3351 100644
--- a/google/cloud/pubsub/schema_admin_connection.h
+++ b/google/cloud/pubsub/schema_admin_connection.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * An input range to stream Cloud Pub/Sub schemas.
@@ -166,16 +166,16 @@ std::shared_ptr<SchemaAdminConnection> MakeSchemaAdminConnection(
     std::unique_ptr<pubsub::RetryPolicy const> retry_policy = {},
     std::unique_ptr<pubsub::BackoffPolicy const> backoff_policy = {});
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<pubsub::SchemaAdminConnection> MakeSchemaAdminConnection(
     Options const& opts, std::shared_ptr<SchemaStub> stub);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema_admin_connection_test.cc b/google/cloud/pubsub/schema_admin_connection_test.cc
index f572fa9e84d3d..d504984c9295b 100644
--- a/google/cloud/pubsub/schema_admin_connection_test.cc
+++ b/google/cloud/pubsub/schema_admin_connection_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -212,7 +212,7 @@ TEST(SchemaAdminConnectionTest, ValidateMessage) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/schema_test.cc b/google/cloud/pubsub/schema_test.cc
index 7a3937df1ec43..88d28210ea1bb 100644
--- a/google/cloud/pubsub/schema_test.cc
+++ b/google/cloud/pubsub/schema_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(Schema, Basics) {
@@ -55,7 +55,7 @@ TEST(Schema, OutputStream) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/snapshot.cc b/google/cloud/pubsub/snapshot.cc
index 0fedf667cb065..8f03fab1fc7e4 100644
--- a/google/cloud/pubsub/snapshot.cc
+++ b/google/cloud/pubsub/snapshot.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string Snapshot::FullName() const {
   return "projects/" + project_id() + "/snapshots/" + snapshot_id();
@@ -31,7 +31,7 @@ std::ostream& operator<<(std::ostream& os, Snapshot const& rhs) {
   return os << rhs.FullName();
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/snapshot.h b/google/cloud/pubsub/snapshot.h
index 5b05d27094dda..9c955c25a9a63 100644
--- a/google/cloud/pubsub/snapshot.h
+++ b/google/cloud/pubsub/snapshot.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Objects of this class identify a Cloud Pub/Sub snapshot.
@@ -76,7 +76,7 @@ class Snapshot {
   std::string snapshot_id_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/snapshot_builder.cc b/google/cloud/pubsub/snapshot_builder.cc
index 26e5d484a75f7..664fd8e8bfed9 100644
--- a/google/cloud/pubsub/snapshot_builder.cc
+++ b/google/cloud/pubsub/snapshot_builder.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 google::pubsub::v1::CreateSnapshotRequest SnapshotBuilder::BuildCreateRequest(
     Subscription const& subscription) && {
@@ -49,7 +49,7 @@ google::pubsub::v1::UpdateSnapshotRequest SnapshotBuilder::BuildUpdateRequest(
   return request;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/snapshot_builder.h b/google/cloud/pubsub/snapshot_builder.h
index 23b4deacf98a2..cc6d6fe8aac61 100644
--- a/google/cloud/pubsub/snapshot_builder.h
+++ b/google/cloud/pubsub/snapshot_builder.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Build a request to create a Cloud Pub/Sub snapshot.
@@ -73,7 +73,7 @@ class SnapshotBuilder {
   std::set<std::string> paths_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/snapshot_builder_test.cc b/google/cloud/pubsub/snapshot_builder_test.cc
index 468aaf42256b5..76adaf89acbfb 100644
--- a/google/cloud/pubsub/snapshot_builder_test.cc
+++ b/google/cloud/pubsub/snapshot_builder_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -109,7 +109,7 @@ TEST(SnapshotBuilder, UpdateClearLabels) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/snapshot_test.cc b/google/cloud/pubsub/snapshot_test.cc
index 4cc4e5882bcc5..685f07cf7b772 100644
--- a/google/cloud/pubsub/snapshot_test.cc
+++ b/google/cloud/pubsub/snapshot_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(Snapshot, Basics) {
@@ -55,7 +55,7 @@ TEST(Snapshot, OutputStream) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscriber.h b/google/cloud/pubsub/subscriber.h
index 32a0cbcba5974..220e206dad8c9 100644
--- a/google/cloud/pubsub/subscriber.h
+++ b/google/cloud/pubsub/subscriber.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Receive messages from the Cloud Pub/Sub service.
  *
@@ -135,7 +135,7 @@ class Subscriber {
   std::shared_ptr<SubscriberConnection> connection_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscriber_connection.cc b/google/cloud/pubsub/subscriber_connection.cc
index da357772e65f5..0284280672d37 100644
--- a/google/cloud/pubsub/subscriber_connection.cc
+++ b/google/cloud/pubsub/subscriber_connection.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 SubscriberConnection::~SubscriberConnection() = default;
 
@@ -74,11 +74,11 @@ std::shared_ptr<SubscriberConnection> MakeSubscriberConnection(
   return MakeSubscriberConnection(std::move(subscription), std::move(opts));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 class SubscriberConnectionImpl : public pubsub::SubscriberConnection {
  public:
@@ -133,7 +133,7 @@ std::shared_ptr<pubsub::SubscriberConnection> MakeSubscriberConnection(
       std::move(subscription), std::move(opts), std::move(stub));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscriber_connection.h b/google/cloud/pubsub/subscriber_connection.h
index b2b23ed9b6ceb..a09b0e6eca9dd 100644
--- a/google/cloud/pubsub/subscriber_connection.h
+++ b/google/cloud/pubsub/subscriber_connection.h
@@ -34,7 +34,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A connection to the Cloud Pub/Sub service to receive events.
@@ -155,17 +155,17 @@ std::shared_ptr<SubscriberConnection> MakeSubscriberConnection(
     std::unique_ptr<pubsub::RetryPolicy const> retry_policy = {},
     std::unique_ptr<pubsub::BackoffPolicy const> backoff_policy = {});
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<pubsub::SubscriberConnection> MakeSubscriberConnection(
     pubsub::Subscription subscription, Options opts,
     std::vector<std::shared_ptr<SubscriberStub>> stubs);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscriber_connection_test.cc b/google/cloud/pubsub/subscriber_connection_test.cc
index 34b7e9fe4b0d0..4251b3248b7d3 100644
--- a/google/cloud/pubsub/subscriber_connection_test.cc
+++ b/google/cloud/pubsub/subscriber_connection_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::pubsub_testing::FakeAsyncStreamingPull;
@@ -243,7 +243,7 @@ TEST(SubscriberConnectionTest, MakeSubscriberConnectionSetupsMetadata) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscriber_options.cc b/google/cloud/pubsub/subscriber_options.cc
index bb4333ab24519..a96889754aaf2 100644
--- a/google/cloud/pubsub/subscriber_options.cc
+++ b/google/cloud/pubsub/subscriber_options.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using seconds = std::chrono::seconds;
 
@@ -54,7 +54,7 @@ SubscriberOptions& SubscriberOptions::set_max_concurrency(std::size_t v) {
   return *this;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscriber_options.h b/google/cloud/pubsub/subscriber_options.h
index 0714451d60bee..8fd6d7c84e15e 100644
--- a/google/cloud/pubsub/subscriber_options.h
+++ b/google/cloud/pubsub/subscriber_options.h
@@ -24,19 +24,19 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class SubscriberOptions;
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 Options MakeOptions(pubsub::SubscriberOptions);
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Configure how a `Subscriber` handles incoming messages.
@@ -241,17 +241,17 @@ class SubscriberOptions {
   Options opts_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 inline Options MakeOptions(pubsub::SubscriberOptions o) {
   return std::move(o.opts_);
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscriber_options_test.cc b/google/cloud/pubsub/subscriber_options_test.cc
index 70a762551795a..d974d5ce46950 100644
--- a/google/cloud/pubsub/subscriber_options_test.cc
+++ b/google/cloud/pubsub/subscriber_options_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using std::chrono::seconds;
@@ -119,7 +119,7 @@ TEST(SubscriberOptionsTest, MakeOptions) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscriber_test.cc b/google/cloud/pubsub/subscriber_test.cc
index 66426680fd09a..84fcd89d457fd 100644
--- a/google/cloud/pubsub/subscriber_test.cc
+++ b/google/cloud/pubsub/subscriber_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 /// @test Verify Subscriber::Subscribe() works, including mocks.
@@ -77,7 +77,7 @@ TEST(SubscriberTest, SubscribeWithOptions) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription.cc b/google/cloud/pubsub/subscription.cc
index 580c7df3981c9..7f3432161bd97 100644
--- a/google/cloud/pubsub/subscription.cc
+++ b/google/cloud/pubsub/subscription.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string Subscription::FullName() const {
   return "projects/" + project_id() + "/subscriptions/" + subscription_id();
@@ -32,7 +32,7 @@ std::ostream& operator<<(std::ostream& os, Subscription const& rhs) {
   return os << rhs.FullName();
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription.h b/google/cloud/pubsub/subscription.h
index 9e27c6692e606..b0bbe09965149 100644
--- a/google/cloud/pubsub/subscription.h
+++ b/google/cloud/pubsub/subscription.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Objects of this class identify a Cloud Pub/Sub subscription.
@@ -76,7 +76,7 @@ class Subscription {
   std::string subscription_id_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_admin_client.cc b/google/cloud/pubsub/subscription_admin_client.cc
index 56efb79fdc22e..3e74c11b4517e 100644
--- a/google/cloud/pubsub/subscription_admin_client.cc
+++ b/google/cloud/pubsub/subscription_admin_client.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 SubscriptionAdminClient::SubscriptionAdminClient(
     std::shared_ptr<SubscriptionAdminConnection> connection)
@@ -41,7 +41,7 @@ StatusOr<google::pubsub::v1::SeekResponse> SubscriptionAdminClient::Seek(
   return connection_->Seek({std::move(request)});
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_admin_client.h b/google/cloud/pubsub/subscription_admin_client.h
index 73f28fc1e8f53..1f9f2c63dbf7e 100644
--- a/google/cloud/pubsub/subscription_admin_client.h
+++ b/google/cloud/pubsub/subscription_admin_client.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Performs subscription administrative operations in Cloud Pub/Sub.
@@ -340,7 +340,7 @@ class SubscriptionAdminClient {
   std::shared_ptr<SubscriptionAdminConnection> connection_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_admin_client_test.cc b/google/cloud/pubsub/subscription_admin_client_test.cc
index 7e7a753a887a7..f29e85ce1b9cd 100644
--- a/google/cloud/pubsub/subscription_admin_client_test.cc
+++ b/google/cloud/pubsub/subscription_admin_client_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::ElementsAre;
@@ -273,7 +273,7 @@ TEST(SubscriptionAdminClient, Seek) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_admin_connection.cc b/google/cloud/pubsub/subscription_admin_connection.cc
index a995126e7a147..300f7e91d4886 100644
--- a/google/cloud/pubsub/subscription_admin_connection.cc
+++ b/google/cloud/pubsub/subscription_admin_connection.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::Idempotency;
@@ -286,11 +286,11 @@ MakeSubscriptionAdminConnection(Options const& opts,
       opts.get<pubsub::BackoffPolicyOption>()->clone());
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<SubscriptionAdminConnection> MakeSubscriptionAdminConnection(
     std::initializer_list<pubsub_internal::NonConstructible>) {
@@ -392,7 +392,7 @@ StatusOr<google::pubsub::v1::SeekResponse> SubscriptionAdminConnection::Seek(
   return Status{StatusCode::kUnimplemented, "needs-override"};
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_admin_connection.h b/google/cloud/pubsub/subscription_admin_connection.h
index aa0313ffd70db..88f2d824dce6c 100644
--- a/google/cloud/pubsub/subscription_admin_connection.h
+++ b/google/cloud/pubsub/subscription_admin_connection.h
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * An input range to stream Cloud Pub/Sub subscriptions.
@@ -260,17 +260,17 @@ std::shared_ptr<SubscriptionAdminConnection> MakeSubscriptionAdminConnection(
     std::unique_ptr<pubsub::RetryPolicy const> retry_policy = {},
     std::unique_ptr<pubsub::BackoffPolicy const> backoff_policy = {});
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<pubsub::SubscriptionAdminConnection>
 MakeSubscriptionAdminConnection(Options const& opts,
                                 std::shared_ptr<SubscriberStub> stub);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_admin_connection_test.cc b/google/cloud/pubsub/subscription_admin_connection_test.cc
index 595ed1cfe935e..47586830da645 100644
--- a/google/cloud/pubsub/subscription_admin_connection_test.cc
+++ b/google/cloud/pubsub/subscription_admin_connection_test.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsContextMDValid;
@@ -379,7 +379,7 @@ TEST(SubscriptionAdminConnectionTest, Seek) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_builder.cc b/google/cloud/pubsub/subscription_builder.cc
index 373a98061b958..4f960e19c0b38 100644
--- a/google/cloud/pubsub/subscription_builder.cc
+++ b/google/cloud/pubsub/subscription_builder.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 google::pubsub::v1::ModifyPushConfigRequest
 PushConfigBuilder::BuildModifyPushConfig(Subscription const& subscription) && {
@@ -63,7 +63,7 @@ SubscriptionBuilder& SubscriptionBuilder::set_push_config(
   return *this;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_builder.h b/google/cloud/pubsub/subscription_builder.h
index 2d5667228b92e..4e1033e3a43f7 100644
--- a/google/cloud/pubsub/subscription_builder.h
+++ b/google/cloud/pubsub/subscription_builder.h
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class SubscriptionBuilder;
 
 /**
@@ -278,7 +278,7 @@ class SubscriptionBuilder {
   std::set<std::string> paths_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_builder_test.cc b/google/cloud/pubsub/subscription_builder_test.cc
index 4d58e30c9ddc0..28a5315a2c68e 100644
--- a/google/cloud/pubsub/subscription_builder_test.cc
+++ b/google/cloud/pubsub/subscription_builder_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -516,7 +516,7 @@ TEST(SubscriptionBuilder, MakeExpirationPolicy) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/subscription_test.cc b/google/cloud/pubsub/subscription_test.cc
index b6377d3c6fb20..8a211babdb8f6 100644
--- a/google/cloud/pubsub/subscription_test.cc
+++ b/google/cloud/pubsub/subscription_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(Subscription, Basics) {
@@ -55,7 +55,7 @@ TEST(Subscription, OutputStream) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/fake_streaming_pull.cc b/google/cloud/pubsub/testing/fake_streaming_pull.cc
index 8e8490b3bca94..1236fa48f26fa 100644
--- a/google/cloud/pubsub/testing/fake_streaming_pull.cc
+++ b/google/cloud/pubsub/testing/fake_streaming_pull.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::testing::AtLeast;
 using ::testing::AtMost;
@@ -87,7 +87,7 @@ std::unique_ptr<pubsub_testing::MockAsyncPullStream> FakeAsyncStreamingPull(
   return stream;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/fake_streaming_pull.h b/google/cloud/pubsub/testing/fake_streaming_pull.h
index 35424c5d3b845..115fe58d0e00e 100644
--- a/google/cloud/pubsub/testing/fake_streaming_pull.h
+++ b/google/cloud/pubsub/testing/fake_streaming_pull.h
@@ -21,13 +21,13 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::unique_ptr<pubsub_testing::MockAsyncPullStream> FakeAsyncStreamingPull(
     google::cloud::CompletionQueue& cq, std::unique_ptr<grpc::ClientContext>,
     google::pubsub::v1::StreamingPullRequest const&);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/mock_batch_sink.h b/google/cloud/pubsub/testing/mock_batch_sink.h
index 8bab42a09230d..7e9ed5df19fd6 100644
--- a/google/cloud/pubsub/testing/mock_batch_sink.h
+++ b/google/cloud/pubsub/testing/mock_batch_sink.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A class to mock pubsub_internal::BatchSink
@@ -37,7 +37,7 @@ class MockBatchSink : public pubsub_internal::BatchSink {
   MOCK_METHOD(void, ResumePublish, (std::string const&), (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/mock_publisher_stub.h b/google/cloud/pubsub/testing/mock_publisher_stub.h
index 8daee5a0a7998..3fbcb2f18f2d4 100644
--- a/google/cloud/pubsub/testing/mock_publisher_stub.h
+++ b/google/cloud/pubsub/testing/mock_publisher_stub.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A class to mock pubsub_internal::PublisherStub
@@ -81,7 +81,7 @@ class MockPublisherStub : public pubsub_internal::PublisherStub {
               (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/mock_schema_stub.h b/google/cloud/pubsub/testing/mock_schema_stub.h
index f1d8b6b2d6894..de089523a87b5 100644
--- a/google/cloud/pubsub/testing/mock_schema_stub.h
+++ b/google/cloud/pubsub/testing/mock_schema_stub.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A class to mock pubsub_internal::SchemaStub
@@ -59,7 +59,7 @@ class MockSchemaStub : public pubsub_internal::SchemaStub {
               (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/mock_subscriber_stub.h b/google/cloud/pubsub/testing/mock_subscriber_stub.h
index 3c99af305b8d3..1dfffeef93698 100644
--- a/google/cloud/pubsub/testing/mock_subscriber_stub.h
+++ b/google/cloud/pubsub/testing/mock_subscriber_stub.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A class to mock pubsub_internal::SubscriberStub
@@ -126,7 +126,7 @@ class MockAsyncPullStream
   MOCK_METHOD(future<Status>, Finish, (), (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/mock_subscription_batch_source.h b/google/cloud/pubsub/testing/mock_subscription_batch_source.h
index e76696bcd7e16..beda362dbfb51 100644
--- a/google/cloud/pubsub/testing/mock_subscription_batch_source.h
+++ b/google/cloud/pubsub/testing/mock_subscription_batch_source.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class MockSubscriptionBatchSource
     : public pubsub_internal::SubscriptionBatchSource {
@@ -41,7 +41,7 @@ class MockSubscriptionBatchSource
               (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/mock_subscription_message_source.h b/google/cloud/pubsub/testing/mock_subscription_message_source.h
index 6cd24fd026260..5016b66753419 100644
--- a/google/cloud/pubsub/testing/mock_subscription_message_source.h
+++ b/google/cloud/pubsub/testing/mock_subscription_message_source.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class MockSubscriptionMessageSource
     : public pubsub_internal::SubscriptionMessageSource {
@@ -35,7 +35,7 @@ class MockSubscriptionMessageSource
   MOCK_METHOD(void, NackMessage, (std::string const& ack_id), (override));
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/random_names.cc b/google/cloud/pubsub/testing/random_names.cc
index 3593cb06b2d02..691cadd4132d7 100644
--- a/google/cloud/pubsub/testing/random_names.cc
+++ b/google/cloud/pubsub/testing/random_names.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string RandomTopicId(google::cloud::internal::DefaultPRNG& generator,
                           std::string const& prefix) {
@@ -73,7 +73,7 @@ std::string RandomSchemaId(google::cloud::internal::DefaultPRNG& generator,
   return p + "-" + suffix;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/random_names.h b/google/cloud/pubsub/testing/random_names.h
index 210e397a07d34..ca2aa442a6575 100644
--- a/google/cloud/pubsub/testing/random_names.h
+++ b/google/cloud/pubsub/testing/random_names.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Generate a random topic ID.
 std::string RandomTopicId(google::cloud::internal::DefaultPRNG& generator,
@@ -41,7 +41,7 @@ std::string RandomSnapshotId(google::cloud::internal::DefaultPRNG& generator,
 std::string RandomSchemaId(google::cloud::internal::DefaultPRNG& generator,
                            std::string const& prefix = {});
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/test_retry_policies.cc b/google/cloud/pubsub/testing/test_retry_policies.cc
index 4d09d509a15ba..af65e8d3d366e 100644
--- a/google/cloud/pubsub/testing/test_retry_policies.cc
+++ b/google/cloud/pubsub/testing/test_retry_policies.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Options MakeTestOptions(Options opts) {
   if (!opts.has<pubsub::RetryPolicyOption>()) {
@@ -35,7 +35,7 @@ Options MakeTestOptions(Options opts) {
   return opts;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/testing/test_retry_policies.h b/google/cloud/pubsub/testing/test_retry_policies.h
index 7825ac74d227b..905c95fc7d91a 100644
--- a/google/cloud/pubsub/testing/test_retry_policies.h
+++ b/google/cloud/pubsub/testing/test_retry_policies.h
@@ -24,11 +24,11 @@
 namespace google {
 namespace cloud {
 namespace pubsub_testing {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Options MakeTestOptions(Options opts = {});
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic.cc b/google/cloud/pubsub/topic.cc
index 3eb5e4e9a4e51..8652ab257ae3c 100644
--- a/google/cloud/pubsub/topic.cc
+++ b/google/cloud/pubsub/topic.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string Topic::FullName() const {
   return "projects/" + project_id() + "/topics/" + topic_id();
@@ -31,7 +31,7 @@ std::ostream& operator<<(std::ostream& os, Topic const& rhs) {
   return os << rhs.FullName();
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic.h b/google/cloud/pubsub/topic.h
index dc4bd056e49f1..cc158132d3785 100644
--- a/google/cloud/pubsub/topic.h
+++ b/google/cloud/pubsub/topic.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Objects of this class identify a Cloud Pub/Sub topic.
@@ -73,7 +73,7 @@ class Topic {
   std::string topic_id_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_admin_client.cc b/google/cloud/pubsub/topic_admin_client.cc
index 5c062ee877462..e455d6367a4b6 100644
--- a/google/cloud/pubsub/topic_admin_client.cc
+++ b/google/cloud/pubsub/topic_admin_client.cc
@@ -17,13 +17,13 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 TopicAdminClient::TopicAdminClient(
     std::shared_ptr<TopicAdminConnection> connection)
     : connection_(std::move(connection)) {}
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_admin_client.h b/google/cloud/pubsub/topic_admin_client.h
index 6941a063706fc..49aaf7ea338cf 100644
--- a/google/cloud/pubsub/topic_admin_client.h
+++ b/google/cloud/pubsub/topic_admin_client.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Performs topic admin operations in Cloud Pub/Sub.
@@ -215,7 +215,7 @@ class TopicAdminClient {
   std::shared_ptr<TopicAdminConnection> connection_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_admin_client_test.cc b/google/cloud/pubsub/topic_admin_client_test.cc
index 43269cf67057d..059f4c3c2eec9 100644
--- a/google/cloud/pubsub/topic_admin_client_test.cc
+++ b/google/cloud/pubsub/topic_admin_client_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::ElementsAre;
@@ -202,7 +202,7 @@ TEST(TopicAdminClient, ListTopicSnapshots) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_admin_connection.cc b/google/cloud/pubsub/topic_admin_connection.cc
index b8b37ca9913df..14405ffcafb86 100644
--- a/google/cloud/pubsub/topic_admin_connection.cc
+++ b/google/cloud/pubsub/topic_admin_connection.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::Idempotency;
@@ -258,11 +258,11 @@ std::shared_ptr<pubsub::TopicAdminConnection> MakeTopicAdminConnection(
       opts.get<pubsub::BackoffPolicyOption>()->clone());
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 TopicAdminConnection::~TopicAdminConnection() = default;
 
@@ -343,7 +343,7 @@ std::shared_ptr<TopicAdminConnection> MakeTopicAdminConnection(
   return MakeTopicAdminConnection(std::move(opts));
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_admin_connection.h b/google/cloud/pubsub/topic_admin_connection.h
index 137b598e95bc4..eeb703dd1b5f0 100644
--- a/google/cloud/pubsub/topic_admin_connection.h
+++ b/google/cloud/pubsub/topic_admin_connection.h
@@ -32,7 +32,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * An input range to stream Cloud Pub/Sub topics.
@@ -231,16 +231,16 @@ std::shared_ptr<TopicAdminConnection> MakeTopicAdminConnection(
     std::unique_ptr<pubsub::RetryPolicy const> retry_policy = {},
     std::unique_ptr<pubsub::BackoffPolicy const> backoff_policy = {});
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 
 namespace pubsub_internal {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<pubsub::TopicAdminConnection> MakeTopicAdminConnection(
     Options const& opts, std::shared_ptr<PublisherStub> stub);
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_admin_connection_test.cc b/google/cloud/pubsub/topic_admin_connection_test.cc
index fac0b6274a845..6dba38dc47214 100644
--- a/google/cloud/pubsub/topic_admin_connection_test.cc
+++ b/google/cloud/pubsub/topic_admin_connection_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -253,7 +253,7 @@ TEST(TopicAdminConnectionTest, ListSnapshots) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_builder.cc b/google/cloud/pubsub/topic_builder.cc
index 1b216c46e422d..c63bb847975a9 100644
--- a/google/cloud/pubsub/topic_builder.cc
+++ b/google/cloud/pubsub/topic_builder.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 google::pubsub::v1::Topic TopicBuilder::BuildCreateRequest() && {
   return std::move(proto_);
@@ -34,7 +34,7 @@ google::pubsub::v1::UpdateTopicRequest TopicBuilder::BuildUpdateRequest() && {
   return request;
 }
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_builder.h b/google/cloud/pubsub/topic_builder.h
index c8c2500aae954..fefb29425b5c1 100644
--- a/google/cloud/pubsub/topic_builder.h
+++ b/google/cloud/pubsub/topic_builder.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Builds requests to create or update a Cloud Pub/Sub topic.
@@ -134,7 +134,7 @@ class TopicBuilder {
   std::set<std::string> paths_;
 };
 
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_builder_test.cc b/google/cloud/pubsub/topic_builder_test.cc
index 69d387e4a5d3d..c878f27b65ae5 100644
--- a/google/cloud/pubsub/topic_builder_test.cc
+++ b/google/cloud/pubsub/topic_builder_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -217,7 +217,7 @@ TEST(TopicBuilder, MultipleChanges) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/topic_test.cc b/google/cloud/pubsub/topic_test.cc
index d321e8a25dfa7..c466269dde3c3 100644
--- a/google/cloud/pubsub/topic_test.cc
+++ b/google/cloud/pubsub/topic_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace pubsub {
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(Topic, Basics) {
@@ -55,7 +55,7 @@ TEST(Topic, OutputStream) {
 }
 
 }  // namespace
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/pubsub/version.h b/google/cloud/pubsub/version.h
index e50f4623a6925..6c8101e6c20bc 100644
--- a/google/cloud/pubsub/version.h
+++ b/google/cloud/pubsub/version.h
@@ -18,6 +18,9 @@
 #include "google/cloud/pubsub/version_info.h"
 #include "google/cloud/version.h"
 
+// This preprocessor symbol is deprecated and should never be used anywhere. It
+// exists solely for backward compatibility to avoid breaking anyone who may
+// have been using it.
 #define GOOGLE_CLOUD_CPP_PUBSUB_NS GOOGLE_CLOUD_CPP_NS
 
 namespace google {
@@ -38,8 +41,7 @@ namespace pubsub {
  * `pubsub::Foo` in their source, but the symbols are versioned, i.e., the
  * symbol becomes `pubsub::v1::Foo`.
  */
-inline namespace GOOGLE_CLOUD_CPP_PUBSUB_NS {
-}  // namespace GOOGLE_CLOUD_CPP_PUBSUB_NS
+inline namespace GOOGLE_CLOUD_CPP_NS {}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace pubsub
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/admin/integration_tests/backup_extra_integration_test.cc b/google/cloud/spanner/admin/integration_tests/backup_extra_integration_test.cc
index 99ac6ebed0c55..091c5e79b23eb 100644
--- a/google/cloud/spanner/admin/integration_tests/backup_extra_integration_test.cc
+++ b/google/cloud/spanner/admin/integration_tests/backup_extra_integration_test.cc
@@ -40,7 +40,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -478,7 +478,7 @@ TEST_F(BackupExtraIntegrationTest, BackupRestoreWithCMEK) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/admin/integration_tests/backup_integration_test.cc b/google/cloud/spanner/admin/integration_tests/backup_integration_test.cc
index bb045962dd5b6..7fd9ce32ec601 100644
--- a/google/cloud/spanner/admin/integration_tests/backup_integration_test.cc
+++ b/google/cloud/spanner/admin/integration_tests/backup_integration_test.cc
@@ -40,7 +40,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 std::string const& ProjectId() {
@@ -227,7 +227,7 @@ TEST_F(BackupIntegrationTest, BackupRestore) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/admin/integration_tests/database_admin_integration_test.cc b/google/cloud/spanner/admin/integration_tests/database_admin_integration_test.cc
index 7d2ed0403063b..a2a47d69aefdb 100644
--- a/google/cloud/spanner/admin/integration_tests/database_admin_integration_test.cc
+++ b/google/cloud/spanner/admin/integration_tests/database_admin_integration_test.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -528,7 +528,7 @@ TEST_F(DatabaseAdminClientTest, CreateWithNonexistentEncryptionKey) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/admin/integration_tests/instance_admin_integration_test.cc b/google/cloud/spanner/admin/integration_tests/instance_admin_integration_test.cc
index fc7b21edad4db..a5f16beba28a1 100644
--- a/google/cloud/spanner/admin/integration_tests/instance_admin_integration_test.cc
+++ b/google/cloud/spanner/admin/integration_tests/instance_admin_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -261,7 +261,7 @@ TEST_F(InstanceAdminClientTest, InstanceIam) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/backoff_policy.h b/google/cloud/spanner/backoff_policy.h
index 29e10d940a3cb..8e3d97e770d10 100644
--- a/google/cloud/spanner/backoff_policy.h
+++ b/google/cloud/spanner/backoff_policy.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// The base class for backoff policies.
 using BackoffPolicy = ::google::cloud::internal::BackoffPolicy;
@@ -30,7 +30,7 @@ using BackoffPolicy = ::google::cloud::internal::BackoffPolicy;
 using ExponentialBackoffPolicy =
     google::cloud::internal::ExponentialBackoffPolicy;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/backup.cc b/google/cloud/spanner/backup.cc
index 9d511046f4c86..e02a1ad392a42 100644
--- a/google/cloud/spanner/backup.cc
+++ b/google/cloud/spanner/backup.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Backup::Backup(Instance instance, std::string backup_id)
     : instance_(std::move(instance)), backup_id_(std::move(backup_id)) {}
@@ -49,7 +49,7 @@ StatusOr<Backup> MakeBackup(std::string const& full_name) {
                 std::move(matches[3]));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/backup.h b/google/cloud/spanner/backup.h
index 7cebb68937cec..56b7cc2c30f72 100644
--- a/google/cloud/spanner/backup.h
+++ b/google/cloud/spanner/backup.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * This class identifies a Cloud Spanner Backup.
@@ -84,7 +84,7 @@ class Backup {
  */
 StatusOr<Backup> MakeBackup(std::string const& full_name);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/backup_test.cc b/google/cloud/spanner/backup_test.cc
index 1867cd47e2a91..8968c6f1e0ffc 100644
--- a/google/cloud/spanner/backup_test.cc
+++ b/google/cloud/spanner/backup_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -83,7 +83,7 @@ TEST(Backup, MakeBackup) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/batch_dml_result.h b/google/cloud/spanner/batch_dml_result.h
index 7600093e6d59f..8a3d44e1ad091 100644
--- a/google/cloud/spanner/batch_dml_result.h
+++ b/google/cloud/spanner/batch_dml_result.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * The result of executing a batch of DML statements.
@@ -51,7 +51,7 @@ struct BatchDmlResult {
   Status status;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/benchmarks/benchmarks_config.cc b/google/cloud/spanner/benchmarks/benchmarks_config.cc
index 9384ff7eb022e..9494e2b276329 100644
--- a/google/cloud/spanner/benchmarks/benchmarks_config.cc
+++ b/google/cloud/spanner/benchmarks/benchmarks_config.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_benchmarks {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::ostream& operator<<(std::ostream& os, Config const& config) {
   return os << "# Experiment: " << config.experiment
@@ -192,7 +192,7 @@ google::cloud::StatusOr<Config> ParseArgs(std::vector<std::string> args) {
   return config;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_benchmarks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/benchmarks/benchmarks_config.h b/google/cloud/spanner/benchmarks/benchmarks_config.h
index 093260eeed1b1..7fe9764ecef33 100644
--- a/google/cloud/spanner/benchmarks/benchmarks_config.h
+++ b/google/cloud/spanner/benchmarks/benchmarks_config.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_benchmarks {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 struct Config {
   std::string experiment;
@@ -52,7 +52,7 @@ std::ostream& operator<<(std::ostream& os, Config const& config);
 
 google::cloud::StatusOr<Config> ParseArgs(std::vector<std::string> args);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_benchmarks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/benchmarks/benchmarks_config_test.cc b/google/cloud/spanner/benchmarks/benchmarks_config_test.cc
index 3b117088be908..c1d22aa4cce2c 100644
--- a/google/cloud/spanner/benchmarks/benchmarks_config_test.cc
+++ b/google/cloud/spanner/benchmarks/benchmarks_config_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_benchmarks {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 using ::google::cloud::testing_util::StatusIs;
 
@@ -134,7 +134,7 @@ TEST(BenchmarkConfigTest, OnlyClients) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_benchmarks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/bytes.cc b/google/cloud/spanner/bytes.cc
index 12dd6a2fd8f39..d33be5612e713 100644
--- a/google/cloud/spanner/bytes.cc
+++ b/google/cloud/spanner/bytes.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::Base64Decoder;
 
@@ -53,11 +53,11 @@ std::ostream& operator<<(std::ostream& os, Bytes const& bytes) {
   return os << "\"";
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct BytesInternals {
   static spanner::Bytes Create(std::string rep) {
     spanner::Bytes bytes;
@@ -82,7 +82,7 @@ std::string BytesToBase64(spanner::Bytes b) {
   return BytesInternals::GetRep(std::move(b));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/bytes.h b/google/cloud/spanner/bytes.h
index 5340ccb0bb4c1..bcfa603ea3b8d 100644
--- a/google/cloud/spanner/bytes.h
+++ b/google/cloud/spanner/bytes.h
@@ -26,13 +26,13 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct BytesInternals;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A representation of the Spanner BYTES type: variable-length binary data.
@@ -82,19 +82,19 @@ class Bytes {
   friend std::ostream& operator<<(std::ostream& os, Bytes const& bytes);
 
  private:
-  friend struct spanner_internal::SPANNER_CLIENT_NS::BytesInternals;
+  friend struct spanner_internal::GOOGLE_CLOUD_CPP_NS::BytesInternals;
 
   std::string base64_rep_;  // valid base64 representation
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 StatusOr<spanner::Bytes> BytesFromBase64(std::string input);
 std::string BytesToBase64(spanner::Bytes b);
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 }  // namespace cloud
diff --git a/google/cloud/spanner/bytes_benchmark.cc b/google/cloud/spanner/bytes_benchmark.cc
index a0195455e4f2f..9fd67ee4f5d6a 100644
--- a/google/cloud/spanner/bytes_benchmark.cc
+++ b/google/cloud/spanner/bytes_benchmark.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 // Run on (6 X 2300 MHz CPU s)
@@ -82,7 +82,7 @@ void BM_BytesGet(benchmark::State& state) {
 BENCHMARK(BM_BytesGet);
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/bytes_test.cc b/google/cloud/spanner/bytes_test.cc
index 4f31a2e66df80..326893182ea73 100644
--- a/google/cloud/spanner/bytes_test.cc
+++ b/google/cloud/spanner/bytes_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(Bytes, RoundTrip) {
@@ -164,7 +164,7 @@ TEST(Bytes, OutputStreamEscapingCannotFail) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/client.cc b/google/cloud/spanner/client.cc
index 8b79aab6a68dd..1e64dc81a635d 100644
--- a/google/cloud/spanner/client.cc
+++ b/google/cloud/spanner/client.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 RowStream Client::Read(std::string table, KeySet keys,
                        std::vector<std::string> columns,
@@ -362,11 +362,11 @@ std::shared_ptr<Connection> MakeConnection(
   return MakeConnection(db, std::move(opts));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 // Returns a QueryOptions that has each attribute set according to the
 // preferred/fallback/environment hierarchy.
@@ -414,7 +414,7 @@ spanner::QueryOptions OverlayQueryOptions(
   return opts;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/client.h b/google/cloud/spanner/client.h
index 898e75c972f48..1bd9827606f6a 100644
--- a/google/cloud/spanner/client.h
+++ b/google/cloud/spanner/client.h
@@ -50,7 +50,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 // clang-format off
 /**
@@ -722,11 +722,11 @@ std::shared_ptr<Connection> MakeConnection(
     std::unique_ptr<RetryPolicy> retry_policy,
     std::unique_ptr<BackoffPolicy> backoff_policy);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 spanner::QueryOptions OverlayQueryOptions(
     spanner::QueryOptions const& preferred,
@@ -734,7 +734,7 @@ spanner::QueryOptions OverlayQueryOptions(
     absl::optional<std::string> const& optimizer_version_env,
     absl::optional<std::string> const& optimizer_statistics_package_env);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/client_options.h b/google/cloud/spanner/client_options.h
index ff6048aafbfe2..8692cfb4bdc29 100644
--- a/google/cloud/spanner/client_options.h
+++ b/google/cloud/spanner/client_options.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * ClientOptions allows the caller to set a variety of options when
@@ -56,7 +56,7 @@ class ClientOptions {
   QueryOptions query_options_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/client_options_test.cc b/google/cloud/spanner/client_options_test.cc
index f28c8e45309e1..36ee739cf6b15 100644
--- a/google/cloud/spanner/client_options_test.cc
+++ b/google/cloud/spanner/client_options_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(ClientOptionsTest, OptimizerVersion) {
@@ -38,7 +38,7 @@ TEST(ClientOptionsTest, OptimizerVersion) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/client_test.cc b/google/cloud/spanner/client_test.cc
index c2848a9d7997f..27beabad1590d 100644
--- a/google/cloud/spanner/client_test.cc
+++ b/google/cloud/spanner/client_test.cc
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace spanner_proto = ::google::spanner::v1;
@@ -1193,7 +1193,7 @@ TEST(ClientTest, QueryOptionsOverlayPrecedence) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/commit_options.h b/google/cloud/spanner/commit_options.h
index 3b094f0703776..7098bf706e3e0 100644
--- a/google/cloud/spanner/commit_options.h
+++ b/google/cloud/spanner/commit_options.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Set options on calls to `spanner::Client::Commit()`.
@@ -80,7 +80,7 @@ class CommitOptions {
   absl::optional<std::string> transaction_tag_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/commit_options_test.cc b/google/cloud/spanner/commit_options_test.cc
index cfb496ebbf30b..4d1ae409246f6 100644
--- a/google/cloud/spanner/commit_options_test.cc
+++ b/google/cloud/spanner/commit_options_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(CommitOptionsTest, Defaults) {
@@ -40,7 +40,7 @@ TEST(CommitOptionsTest, SetValues) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/commit_result.h b/google/cloud/spanner/commit_result.h
index dca4a16662891..2b1eb663ab286 100644
--- a/google/cloud/spanner/commit_result.h
+++ b/google/cloud/spanner/commit_result.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Statistics returned for a committed Transaction.
@@ -43,7 +43,7 @@ struct CommitResult {
   absl::optional<CommitStats> commit_stats;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/connection.h b/google/cloud/spanner/connection.h
index d57218928c1b3..f31a33ade4abd 100644
--- a/google/cloud/spanner/connection.h
+++ b/google/cloud/spanner/connection.h
@@ -38,7 +38,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class ReadPartition;
 class QueryPartition;
@@ -168,7 +168,7 @@ class Connection {
   virtual Status Rollback(RollbackParams) = 0;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/connection_options.cc b/google/cloud/spanner/connection_options.cc
index edb57eed0b46f..bd59fe226e490 100644
--- a/google/cloud/spanner/connection_options.cc
+++ b/google/cloud/spanner/connection_options.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string ConnectionOptionsTraits::default_endpoint() {
   return spanner_internal::DefaultOptions().get<EndpointOption>();
@@ -39,7 +39,7 @@ int ConnectionOptionsTraits::default_num_channels() {
   return kNumChannels;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/connection_options.h b/google/cloud/spanner/connection_options.h
index 183e8a59354ef..8dd2e867c3d0d 100644
--- a/google/cloud/spanner/connection_options.h
+++ b/google/cloud/spanner/connection_options.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * The traits to configure `ConnectionOptions<T>` for Cloud Spanner.
@@ -45,7 +45,7 @@ struct ConnectionOptionsTraits {
 using ConnectionOptions =
     google::cloud::ConnectionOptions<ConnectionOptionsTraits>;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 }  // namespace cloud
diff --git a/google/cloud/spanner/connection_options_test.cc b/google/cloud/spanner/connection_options_test.cc
index f429043b896f3..853df11789639 100644
--- a/google/cloud/spanner/connection_options_test.cc
+++ b/google/cloud/spanner/connection_options_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::ScopedEnvironment;
@@ -64,7 +64,7 @@ TEST(DefaultEndpoint, EnvironmentWorks) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/create_instance_request_builder.h b/google/cloud/spanner/create_instance_request_builder.h
index a75a7a348c63b..92ac125f6cb59 100644
--- a/google/cloud/spanner/create_instance_request_builder.h
+++ b/google/cloud/spanner/create_instance_request_builder.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * CreateInstanceRequestBuilder is a builder class for
@@ -129,7 +129,7 @@ class CreateInstanceRequestBuilder {
   google::spanner::admin::instance::v1::CreateInstanceRequest request_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/create_instance_request_builder_test.cc b/google/cloud/spanner/create_instance_request_builder_test.cc
index 75cbf1e139a39..583820af9db7e 100644
--- a/google/cloud/spanner/create_instance_request_builder_test.cc
+++ b/google/cloud/spanner/create_instance_request_builder_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 TEST(CreateInstanceRequestBuilder, DefaultValues) {
   Instance in(Project("test-project"), "test-instance");
@@ -80,7 +80,7 @@ TEST(CreateInstanceRequestBuilder, Lvalue) {
   EXPECT_EQ(expected_display_name, req.instance().display_name());
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/database.cc b/google/cloud/spanner/database.cc
index a6c1ed63a32b1..6dcc8a3fd59a2 100644
--- a/google/cloud/spanner/database.cc
+++ b/google/cloud/spanner/database.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Database::Database(Instance instance, std::string database_id)
     : instance_(std::move(instance)), database_id_(std::move(database_id)) {}
@@ -54,7 +54,7 @@ StatusOr<Database> MakeDatabase(std::string const& full_name) {
                   std::move(matches[3]));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/database.h b/google/cloud/spanner/database.h
index 1ec6a180cd355..6278f382b2b73 100644
--- a/google/cloud/spanner/database.h
+++ b/google/cloud/spanner/database.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * This class identifies a Cloud Spanner Database.
@@ -98,7 +98,7 @@ class Database {
  */
 StatusOr<Database> MakeDatabase(std::string const& full_name);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/database_admin_client.cc b/google/cloud/spanner/database_admin_client.cc
index 74338c9298ae0..522c43f73b68b 100644
--- a/google/cloud/spanner/database_admin_client.cc
+++ b/google/cloud/spanner/database_admin_client.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::database::v1;
 
@@ -222,7 +222,7 @@ ListDatabaseOperationsRange DatabaseAdminClient::ListDatabaseOperations(
   return conn_->ListDatabaseOperations({std::move(in), std::move(filter)});
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/database_admin_client.h b/google/cloud/spanner/database_admin_client.h
index dca6810ab9c96..d73548f61215b 100644
--- a/google/cloud/spanner/database_admin_client.h
+++ b/google/cloud/spanner/database_admin_client.h
@@ -34,7 +34,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Performs database administration operations on Spanner.
@@ -593,7 +593,7 @@ class GOOGLE_CLOUD_CPP_SPANNER_ADMIN_API_DEPRECATED("DatabaseAdminClient")
   std::shared_ptr<DatabaseAdminConnection> conn_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/database_admin_client_test.cc b/google/cloud/spanner/database_admin_client_test.cc
index 6e8dff49d07ce..92d437b822592 100644
--- a/google/cloud/spanner/database_admin_client_test.cc
+++ b/google/cloud/spanner/database_admin_client_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::spanner_mocks::MockDatabaseAdminConnection;
@@ -718,7 +718,7 @@ TEST(DatabaseAdminClientTest, ListDatabaseOperations) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/database_admin_connection.cc b/google/cloud/spanner/database_admin_connection.cc
index 6aaa7c77d4d8a..7edf2d7d662a4 100644
--- a/google/cloud/spanner/database_admin_connection.cc
+++ b/google/cloud/spanner/database_admin_connection.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::database::v1;
 
@@ -634,11 +634,11 @@ std::shared_ptr<DatabaseAdminConnection> MakeDatabaseAdminConnection(
   return MakeDatabaseAdminConnection(std::move(opts));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<spanner::DatabaseAdminConnection>
 MakeDatabaseAdminConnectionForTesting(std::shared_ptr<DatabaseAdminStub> stub,
@@ -648,7 +648,7 @@ MakeDatabaseAdminConnectionForTesting(std::shared_ptr<DatabaseAdminStub> stub,
       std::move(stub), std::move(opts));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/database_admin_connection.h b/google/cloud/spanner/database_admin_connection.h
index 7a564c0cc7342..734fadf1183be 100644
--- a/google/cloud/spanner/database_admin_connection.h
+++ b/google/cloud/spanner/database_admin_connection.h
@@ -36,7 +36,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * An input range to stream all the databases in a Cloud Spanner instance.
@@ -393,18 +393,18 @@ std::shared_ptr<DatabaseAdminConnection> MakeDatabaseAdminConnection(
     std::unique_ptr<BackoffPolicy> backoff_policy,
     std::unique_ptr<PollingPolicy> polling_policy);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Internal-only factory that allows us to inject mock stubs for testing.
 std::shared_ptr<spanner::DatabaseAdminConnection>
 MakeDatabaseAdminConnectionForTesting(std::shared_ptr<DatabaseAdminStub> stub,
                                       Options opts);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 }  // namespace cloud
diff --git a/google/cloud/spanner/database_admin_connection_test.cc b/google/cloud/spanner/database_admin_connection_test.cc
index 2643b49b7ed21..853a66c83c407 100644
--- a/google/cloud/spanner/database_admin_connection_test.cc
+++ b/google/cloud/spanner/database_admin_connection_test.cc
@@ -32,7 +32,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::spanner_testing::MockDatabaseAdminStub;
@@ -1566,7 +1566,7 @@ TEST(DatabaseAdminConnectionTest, ListDatabaseOperationsTooManyFailures) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/database_test.cc b/google/cloud/spanner/database_test.cc
index cbb77eebad025..18add0b8be865 100644
--- a/google/cloud/spanner/database_test.cc
+++ b/google/cloud/spanner/database_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -84,7 +84,7 @@ TEST(Database, MakeDatabase) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/date.h b/google/cloud/spanner/date.h
index 4b2b335bf4a81..cb9d9200aff19 100644
--- a/google/cloud/spanner/date.h
+++ b/google/cloud/spanner/date.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Represents a date in the proleptic Gregorian calendar as a triple of
@@ -35,7 +35,7 @@ inline namespace SPANNER_CLIENT_NS {
  */
 using Date = ::absl::CivilDay;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/encryption_config.h b/google/cloud/spanner/encryption_config.h
index 7c589d947c424..dd9b0243693a1 100644
--- a/google/cloud/spanner/encryption_config.h
+++ b/google/cloud/spanner/encryption_config.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Use the per-operation default encryption:
@@ -60,7 +60,7 @@ class CustomerManagedEncryption {
 using EncryptionConfig = absl::variant<DefaultEncryption, GoogleEncryption,
                                        CustomerManagedEncryption>;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/iam_updater.h b/google/cloud/spanner/iam_updater.h
index 0ebb2f1dff146..95ec69fb85660 100644
--- a/google/cloud/spanner/iam_updater.h
+++ b/google/cloud/spanner/iam_updater.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Type alias for google::cloud::IamUpdater.
@@ -38,7 +38,7 @@ inline namespace SPANNER_CLIENT_NS {
  */
 using IamUpdater = ::google::cloud::IamUpdater;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/instance.cc b/google/cloud/spanner/instance.cc
index 7c5fab2a9014e..b48a1dbf58fd6 100644
--- a/google/cloud/spanner/instance.cc
+++ b/google/cloud/spanner/instance.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Instance::Instance(Project project, std::string instance_id)
     : project_(std::move(project)), instance_id_(std::move(instance_id)) {}
@@ -51,7 +51,7 @@ StatusOr<Instance> MakeInstance(std::string const& full_name) {
   return Instance(Project(std::move(matches[1])), std::move(matches[2]));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/instance.h b/google/cloud/spanner/instance.h
index 5029426dc5791..9050a7afedca3 100644
--- a/google/cloud/spanner/instance.h
+++ b/google/cloud/spanner/instance.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * This class identifies a Cloud Spanner Instance.
@@ -97,7 +97,7 @@ class Instance {
  */
 StatusOr<Instance> MakeInstance(std::string const& full_name);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/instance_admin_client.cc b/google/cloud/spanner/instance_admin_client.cc
index 4112777b26363..1e717a13217df 100644
--- a/google/cloud/spanner/instance_admin_client.cc
+++ b/google/cloud/spanner/instance_admin_client.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<google::spanner::admin::instance::v1::Instance>
 InstanceAdminClient::GetInstance(Instance const& in) {
@@ -123,7 +123,7 @@ InstanceAdminClient::TestIamPermissions(Instance const& in,
   return conn_->TestIamPermissions({in.FullName(), std::move(permissions)});
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/instance_admin_client.h b/google/cloud/spanner/instance_admin_client.h
index 8e4ed6cc388f8..d927572c9e790 100644
--- a/google/cloud/spanner/instance_admin_client.h
+++ b/google/cloud/spanner/instance_admin_client.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Performs instance administration operations on Cloud Spanner.
@@ -306,7 +306,7 @@ class GOOGLE_CLOUD_CPP_SPANNER_ADMIN_API_DEPRECATED("InstanceAdminClient")
   std::shared_ptr<InstanceAdminConnection> conn_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/instance_admin_client_test.cc b/google/cloud/spanner/instance_admin_client_test.cc
index 0d75db882f640..cdaa415f11c54 100644
--- a/google/cloud/spanner/instance_admin_client_test.cc
+++ b/google/cloud/spanner/instance_admin_client_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -313,7 +313,7 @@ TEST(InstanceAdminClientTest, TestIamPermissions) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/instance_admin_connection.cc b/google/cloud/spanner/instance_admin_connection.cc
index b1a2a3a3c40c1..ef401b26435b2 100644
--- a/google/cloud/spanner/instance_admin_connection.cc
+++ b/google/cloud/spanner/instance_admin_connection.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::instance::v1;
 namespace giam = ::google::iam::v1;
@@ -299,11 +299,11 @@ std::shared_ptr<InstanceAdminConnection> MakeInstanceAdminConnection(
   return MakeInstanceAdminConnection(std::move(opts));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::shared_ptr<spanner::InstanceAdminConnection>
 MakeInstanceAdminConnectionForTesting(std::shared_ptr<InstanceAdminStub> stub,
@@ -313,7 +313,7 @@ MakeInstanceAdminConnectionForTesting(std::shared_ptr<InstanceAdminStub> stub,
       std::move(stub), std::move(opts));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/instance_admin_connection.h b/google/cloud/spanner/instance_admin_connection.h
index 356a946f71125..90e5f707b9f44 100644
--- a/google/cloud/spanner/instance_admin_connection.h
+++ b/google/cloud/spanner/instance_admin_connection.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * An input range to stream all the instances in a Cloud project.
@@ -271,18 +271,18 @@ std::shared_ptr<InstanceAdminConnection> MakeInstanceAdminConnection(
     std::unique_ptr<BackoffPolicy> backoff_policy,
     std::unique_ptr<PollingPolicy> polling_policy);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Internal-only factory that allows us to inject mock stubs for testing.
 std::shared_ptr<spanner::InstanceAdminConnection>
 MakeInstanceAdminConnectionForTesting(
     std::shared_ptr<InstanceAdminStub> base_stub, Options opts);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 }  // namespace cloud
diff --git a/google/cloud/spanner/instance_admin_connection_test.cc b/google/cloud/spanner/instance_admin_connection_test.cc
index 73a2e214350f6..6b39b777ced82 100644
--- a/google/cloud/spanner/instance_admin_connection_test.cc
+++ b/google/cloud/spanner/instance_admin_connection_test.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -722,7 +722,7 @@ TEST(InstanceAdminConnectionTest, TestIamPermissionsTooManyTransients) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/instance_test.cc b/google/cloud/spanner/instance_test.cc
index f53313b3befe3..7015143c94d2a 100644
--- a/google/cloud/spanner/instance_test.cc
+++ b/google/cloud/spanner/instance_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -78,7 +78,7 @@ TEST(Instance, MakeInstance) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/backup_extra_integration_test.cc b/google/cloud/spanner/integration_tests/backup_extra_integration_test.cc
index 3704613385e5e..94f8a405e7c51 100644
--- a/google/cloud/spanner/integration_tests/backup_extra_integration_test.cc
+++ b/google/cloud/spanner/integration_tests/backup_extra_integration_test.cc
@@ -36,7 +36,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -426,7 +426,7 @@ TEST_F(BackupExtraIntegrationTest, BackupRestoreWithCMEK) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/backup_integration_test.cc b/google/cloud/spanner/integration_tests/backup_integration_test.cc
index 4868a224f9013..c4eef345c64e5 100644
--- a/google/cloud/spanner/integration_tests/backup_integration_test.cc
+++ b/google/cloud/spanner/integration_tests/backup_integration_test.cc
@@ -36,7 +36,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 std::string const& ProjectId() {
@@ -193,7 +193,7 @@ TEST_F(BackupIntegrationTest, BackupRestore) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/client_integration_test.cc b/google/cloud/spanner/integration_tests/client_integration_test.cc
index dce0ea7fcfc6e..f20ade5b9541b 100644
--- a/google/cloud/spanner/integration_tests/client_integration_test.cc
+++ b/google/cloud/spanner/integration_tests/client_integration_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -968,7 +968,7 @@ TEST_F(ClientIntegrationTest, SpannerStatistics) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/client_stress_test.cc b/google/cloud/spanner/integration_tests/client_stress_test.cc
index ed46f659119d1..b2449f9c6b75a 100644
--- a/google/cloud/spanner/integration_tests/client_stress_test.cc
+++ b/google/cloud/spanner/integration_tests/client_stress_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 using ::google::cloud::StatusOr;
 
@@ -282,7 +282,7 @@ TEST_F(ClientStressTest, UpsertAndRead) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/data_types_integration_test.cc b/google/cloud/spanner/integration_tests/data_types_integration_test.cc
index 4713169d07728..70bed5289eccb 100644
--- a/google/cloud/spanner/integration_tests/data_types_integration_test.cc
+++ b/google/cloud/spanner/integration_tests/data_types_integration_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -478,7 +478,7 @@ TEST_F(DataTypeIntegrationTest, JsonMaxNesting) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/database_admin_integration_test.cc b/google/cloud/spanner/integration_tests/database_admin_integration_test.cc
index 313568aaf5419..8fc2193b470b5 100644
--- a/google/cloud/spanner/integration_tests/database_admin_integration_test.cc
+++ b/google/cloud/spanner/integration_tests/database_admin_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -506,7 +506,7 @@ TEST_F(DatabaseAdminClientTest, CreateWithNonexistentEncryptionKey) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/instance_admin_integration_test.cc b/google/cloud/spanner/integration_tests/instance_admin_integration_test.cc
index a91af3e001f40..fc66896435414 100644
--- a/google/cloud/spanner/integration_tests/instance_admin_integration_test.cc
+++ b/google/cloud/spanner/integration_tests/instance_admin_integration_test.cc
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -263,7 +263,7 @@ TEST_F(InstanceAdminClientTest, InstanceIam) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/rpc_failure_threshold_integration_test.cc b/google/cloud/spanner/integration_tests/rpc_failure_threshold_integration_test.cc
index add7990c98e2d..28db57fade1dc 100644
--- a/google/cloud/spanner/integration_tests/rpc_failure_threshold_integration_test.cc
+++ b/google/cloud/spanner/integration_tests/rpc_failure_threshold_integration_test.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class RpcFailureThresholdTest
@@ -259,7 +259,7 @@ TEST_F(RpcFailureThresholdTest, ExecuteDmlDeleteErrors) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/integration_tests/session_pool_integration_test.cc b/google/cloud/spanner/integration_tests/session_pool_integration_test.cc
index 988b965658d7e..e69a9ba5a5fda 100644
--- a/google/cloud/spanner/integration_tests/session_pool_integration_test.cc
+++ b/google/cloud/spanner/integration_tests/session_pool_integration_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 struct SessionPoolFriendForTest {
   static future<StatusOr<google::spanner::v1::BatchCreateSessionsResponse>>
@@ -117,7 +117,7 @@ TEST_F(SessionPoolIntegrationTest, SessionAsyncCRUD) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/channel.h b/google/cloud/spanner/internal/channel.h
index 715d7984a90a4..8787010fda063 100644
--- a/google/cloud/spanner/internal/channel.h
+++ b/google/cloud/spanner/internal/channel.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * `Channel` represents a single gRPC Channel/Stub.
@@ -40,7 +40,7 @@ struct Channel {
   int session_count = 0;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/clock.h b/google/cloud/spanner/internal/clock.h
index 07de623313041..63c61b796c196 100644
--- a/google/cloud/spanner/internal/clock.h
+++ b/google/cloud/spanner/internal/clock.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A simple `Clock` class that can be overridden for testing.
@@ -55,7 +55,7 @@ using SteadyClock =
 using SystemClock =
     ::google::cloud::spanner_internal::Clock<std::chrono::system_clock>;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/clock_test.cc b/google/cloud/spanner/internal/clock_test.cc
index 4be977f35bb35..35addb30570e7 100644
--- a/google/cloud/spanner/internal/clock_test.cc
+++ b/google/cloud/spanner/internal/clock_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::spanner_testing::FakeClock;
@@ -62,7 +62,7 @@ TEST(Clock, FakeClock) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/connection_impl.cc b/google/cloud/spanner/internal/connection_impl.cc
index d9fb24ca87260..338446fff2a52 100644
--- a/google/cloud/spanner/internal/connection_impl.cc
+++ b/google/cloud/spanner/internal/connection_impl.cc
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::Idempotency;
 
@@ -1052,7 +1052,7 @@ Status ConnectionImpl::RollbackImpl(
   return status;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/connection_impl.h b/google/cloud/spanner/internal/connection_impl.h
index c4e01ce429fff..a215761b8e4e9 100644
--- a/google/cloud/spanner/internal/connection_impl.h
+++ b/google/cloud/spanner/internal/connection_impl.h
@@ -38,7 +38,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A concrete `Connection` subclass that uses gRPC to actually talk to a real
@@ -170,7 +170,7 @@ class ConnectionImpl : public spanner::Connection {
   TracingOptions tracing_options_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/connection_impl_test.cc b/google/cloud/spanner/internal/connection_impl_test.cc
index 373dee6ba345a..5694f18aa52ee 100644
--- a/google/cloud/spanner/internal/connection_impl_test.cc
+++ b/google/cloud/spanner/internal/connection_impl_test.cc
@@ -39,7 +39,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 // We compile with `-Wextra` which enables `-Wmissing-field-initializers`. This
@@ -2938,7 +2938,7 @@ TEST(ConnectionImplTest, OperationsFailOnInvalidatedTransaction) {
 #endif
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/database_admin_logging.cc b/google/cloud/spanner/internal/database_admin_logging.cc
index aa5e0e98356aa..a806fb10ce37e 100644
--- a/google/cloud/spanner/internal/database_admin_logging.cc
+++ b/google/cloud/spanner/internal/database_admin_logging.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::database::v1;
 using ::google::cloud::internal::LogWrapper;
@@ -241,7 +241,7 @@ future<Status> DatabaseAdminLogging::AsyncCancelOperation(
       cq, std::move(context), request, __func__, tracing_options_);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/database_admin_logging.h b/google/cloud/spanner/internal/database_admin_logging.h
index c09ad262ede6f..481d1b15ea887 100644
--- a/google/cloud/spanner/internal/database_admin_logging.h
+++ b/google/cloud/spanner/internal/database_admin_logging.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Implements the logging Decorator for DatabaseAdminStub.
@@ -143,7 +143,7 @@ class DatabaseAdminLogging : public DatabaseAdminStub {
   TracingOptions tracing_options_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/database_admin_logging_test.cc b/google/cloud/spanner/internal/database_admin_logging_test.cc
index 810cc49ea83a0..f6538f17ed2e0 100644
--- a/google/cloud/spanner/internal/database_admin_logging_test.cc
+++ b/google/cloud/spanner/internal/database_admin_logging_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -361,7 +361,7 @@ TEST_F(DatabaseAdminLoggingTest, CancelOperation) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/database_admin_metadata.cc b/google/cloud/spanner/internal/database_admin_metadata.cc
index c17ab3f3301cb..c1b3b49b31c15 100644
--- a/google/cloud/spanner/internal/database_admin_metadata.cc
+++ b/google/cloud/spanner/internal/database_admin_metadata.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::database::v1;
 
@@ -175,7 +175,7 @@ void DatabaseAdminMetadata::SetMetadata(grpc::ClientContext& context,
   context.AddMetadata("x-goog-api-client", api_client_header_);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/database_admin_metadata.h b/google/cloud/spanner/internal/database_admin_metadata.h
index f4a952312e9d8..60a5a41efbfcb 100644
--- a/google/cloud/spanner/internal/database_admin_metadata.h
+++ b/google/cloud/spanner/internal/database_admin_metadata.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Implements the metadata Decorator for DatabaseAdminStub.
  */
@@ -139,7 +139,7 @@ class DatabaseAdminMetadata : public DatabaseAdminStub {
   std::string api_client_header_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/database_admin_metadata_test.cc b/google/cloud/spanner/internal/database_admin_metadata_test.cc
index 7df1397458f56..96cbdd6bdf2c4 100644
--- a/google/cloud/spanner/internal/database_admin_metadata_test.cc
+++ b/google/cloud/spanner/internal/database_admin_metadata_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsContextMDValid;
@@ -471,7 +471,7 @@ TEST_F(DatabaseAdminMetadataTest, CancelOperation) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/database_admin_stub.cc b/google/cloud/spanner/internal/database_admin_stub.cc
index 99682face6623..44486a437f73b 100644
--- a/google/cloud/spanner/internal/database_admin_stub.cc
+++ b/google/cloud/spanner/internal/database_admin_stub.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::database::v1;
 
@@ -302,7 +302,7 @@ std::shared_ptr<DatabaseAdminStub> CreateDefaultDatabaseAdminStub(
   return stub;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/database_admin_stub.h b/google/cloud/spanner/internal/database_admin_stub.h
index 247ad6da1c887..926cf77189d55 100644
--- a/google/cloud/spanner/internal/database_admin_stub.h
+++ b/google/cloud/spanner/internal/database_admin_stub.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Defines the low-level interface for database administration RPCs.
  */
@@ -150,7 +150,7 @@ class DatabaseAdminStub {
 std::shared_ptr<DatabaseAdminStub> CreateDefaultDatabaseAdminStub(
     Options const& opts);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/defaults.cc b/google/cloud/spanner/internal/defaults.cc
index 189c42340c20c..6bd3861c3d87d 100644
--- a/google/cloud/spanner/internal/defaults.cc
+++ b/google/cloud/spanner/internal/defaults.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace {
 
@@ -138,7 +138,7 @@ Options DefaultAdminOptions(Options opts) {
   return opts;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/defaults.h b/google/cloud/spanner/internal/defaults.h
index dfd5a2e3953c5..e28fb23b69598 100644
--- a/google/cloud/spanner/internal/defaults.h
+++ b/google/cloud/spanner/internal/defaults.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Returns an `Options` with the appropriate defaults for Spanner.
@@ -54,7 +54,7 @@ Options DefaultOptions(Options opts = {});
  */
 Options DefaultAdminOptions(Options opts = {});
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/defaults_test.cc b/google/cloud/spanner/internal/defaults_test.cc
index b8b5e4df90d88..15d7653f37d8a 100644
--- a/google/cloud/spanner/internal/defaults_test.cc
+++ b/google/cloud/spanner/internal/defaults_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::AllOf;
@@ -242,7 +242,7 @@ TEST(Options, AppendToUserAgent) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/instance_admin_logging.cc b/google/cloud/spanner/internal/instance_admin_logging.cc
index 7410debf6c269..1db57e20a4ff0 100644
--- a/google/cloud/spanner/internal/instance_admin_logging.cc
+++ b/google/cloud/spanner/internal/instance_admin_logging.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::instance::v1;
 using ::google::cloud::internal::LogWrapper;
@@ -158,7 +158,7 @@ future<Status> InstanceAdminLogging::AsyncCancelOperation(
       cq, std::move(context), request, __func__, tracing_options_);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/instance_admin_logging.h b/google/cloud/spanner/internal/instance_admin_logging.h
index 47b9cfa759bec..dde8b13a48ad4 100644
--- a/google/cloud/spanner/internal/instance_admin_logging.h
+++ b/google/cloud/spanner/internal/instance_admin_logging.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Implements the logging Decorator for InstanceAdminStub.
@@ -108,7 +108,7 @@ class InstanceAdminLogging : public InstanceAdminStub {
   TracingOptions tracing_options_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/instance_admin_logging_test.cc b/google/cloud/spanner/internal/instance_admin_logging_test.cc
index 1c75c017cc0cc..bff6e7aba846d 100644
--- a/google/cloud/spanner/internal/instance_admin_logging_test.cc
+++ b/google/cloud/spanner/internal/instance_admin_logging_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -207,7 +207,7 @@ TEST_F(InstanceAdminLoggingTest, TestIamPermissions) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/instance_admin_metadata.cc b/google/cloud/spanner/internal/instance_admin_metadata.cc
index 99580e437a060..a43309fb2ed54 100644
--- a/google/cloud/spanner/internal/instance_admin_metadata.cc
+++ b/google/cloud/spanner/internal/instance_admin_metadata.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::instance::v1;
 
@@ -120,7 +120,7 @@ void InstanceAdminMetadata::SetMetadata(grpc::ClientContext& context,
   context.AddMetadata("x-goog-api-client", api_client_header_);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/instance_admin_metadata.h b/google/cloud/spanner/internal/instance_admin_metadata.h
index fb15ff27043d0..c9738f215dc26 100644
--- a/google/cloud/spanner/internal/instance_admin_metadata.h
+++ b/google/cloud/spanner/internal/instance_admin_metadata.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Implements the metadata Decorator for InstanceAdminStub.
@@ -104,7 +104,7 @@ class InstanceAdminMetadata : public InstanceAdminStub {
   std::string api_client_header_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/instance_admin_metadata_test.cc b/google/cloud/spanner/internal/instance_admin_metadata_test.cc
index 00aa5f7d93dad..7feb43591233a 100644
--- a/google/cloud/spanner/internal/instance_admin_metadata_test.cc
+++ b/google/cloud/spanner/internal/instance_admin_metadata_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsContextMDValid;
@@ -276,7 +276,7 @@ TEST_F(InstanceAdminMetadataTest, TestIamPermissions) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/instance_admin_stub.cc b/google/cloud/spanner/internal/instance_admin_stub.cc
index c1a76d82cdf40..0503916e00091 100644
--- a/google/cloud/spanner/internal/instance_admin_stub.cc
+++ b/google/cloud/spanner/internal/instance_admin_stub.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace gcsa = ::google::spanner::admin::instance::v1;
 namespace giam = ::google::iam::v1;
@@ -217,7 +217,7 @@ std::shared_ptr<InstanceAdminStub> CreateDefaultInstanceAdminStub(
   return stub;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/instance_admin_stub.h b/google/cloud/spanner/internal/instance_admin_stub.h
index ad21089056035..5d8075cee2002 100644
--- a/google/cloud/spanner/internal/instance_admin_stub.h
+++ b/google/cloud/spanner/internal/instance_admin_stub.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Defines the low-level interface for instance administration RPCs.
@@ -95,7 +95,7 @@ class InstanceAdminStub {
 std::shared_ptr<InstanceAdminStub> CreateDefaultInstanceAdminStub(
     Options const& opts);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/logging_result_set_reader.cc b/google/cloud/spanner/internal/logging_result_set_reader.cc
index efb1b91ff0fa4..73ac25a62c9c9 100644
--- a/google/cloud/spanner/internal/logging_result_set_reader.cc
+++ b/google/cloud/spanner/internal/logging_result_set_reader.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::DebugString;
 
@@ -48,7 +48,7 @@ Status LoggingResultSetReader::Finish() {
   return status;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/logging_result_set_reader.h b/google/cloud/spanner/internal/logging_result_set_reader.h
index 0b4bd9d6cac6c..ff24fc67d2e07 100644
--- a/google/cloud/spanner/internal/logging_result_set_reader.h
+++ b/google/cloud/spanner/internal/logging_result_set_reader.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class LoggingResultSetReader : public PartialResultSetReader {
  public:
@@ -42,7 +42,7 @@ class LoggingResultSetReader : public PartialResultSetReader {
   TracingOptions tracing_options_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/logging_result_set_reader_test.cc b/google/cloud/spanner/internal/logging_result_set_reader_test.cc
index 4d3289f8b1888..9363ba6978384 100644
--- a/google/cloud/spanner/internal/logging_result_set_reader_test.cc
+++ b/google/cloud/spanner/internal/logging_result_set_reader_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -86,7 +86,7 @@ TEST_F(LoggingResultSetReaderTest, Finish) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/logging_spanner_stub.cc b/google/cloud/spanner/internal/logging_spanner_stub.cc
index 917d0668a80f1..db2ef22bf8909 100644
--- a/google/cloud/spanner/internal/logging_spanner_stub.cc
+++ b/google/cloud/spanner/internal/logging_spanner_stub.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace spanner_proto = ::google::spanner::v1;
 using ::google::cloud::internal::LogWrapper;
@@ -226,7 +226,7 @@ StatusOr<spanner_proto::PartitionResponse> LoggingSpannerStub::PartitionRead(
       client_context, request, __func__, tracing_options_);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/logging_spanner_stub.h b/google/cloud/spanner/internal/logging_spanner_stub.h
index aabad5891e889..66aed37e71620 100644
--- a/google/cloud/spanner/internal/logging_spanner_stub.h
+++ b/google/cloud/spanner/internal/logging_spanner_stub.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A SpannerStub that logs each request.
@@ -104,7 +104,7 @@ class LoggingSpannerStub : public SpannerStub {
   TracingOptions tracing_options_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/logging_spanner_stub_test.cc b/google/cloud/spanner/internal/logging_spanner_stub_test.cc
index 6884328210fa5..f7c46b141f807 100644
--- a/google/cloud/spanner/internal/logging_spanner_stub_test.cc
+++ b/google/cloud/spanner/internal/logging_spanner_stub_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Contains;
@@ -258,7 +258,7 @@ TEST_F(LoggingSpannerStubTest, PartitionRead) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/merge_chunk.cc b/google/cloud/spanner/internal/merge_chunk.cc
index 35897ce81d836..496d6b1b24345 100644
--- a/google/cloud/spanner/internal/merge_chunk.cc
+++ b/google/cloud/spanner/internal/merge_chunk.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Status MergeChunk(google::protobuf::Value& value,  // NOLINT(misc-no-recursion)
                   google::protobuf::Value&& chunk) {
@@ -73,7 +73,7 @@ Status MergeChunk(google::protobuf::Value& value,  // NOLINT(misc-no-recursion)
   return Status(StatusCode::kUnknown, "unknown Value type");
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/merge_chunk.h b/google/cloud/spanner/internal/merge_chunk.h
index b92ae32dda2b5..72a4e55ec808c 100644
--- a/google/cloud/spanner/internal/merge_chunk.h
+++ b/google/cloud/spanner/internal/merge_chunk.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Merges @p chunk into @p value, or returns an error.
@@ -47,7 +47,7 @@ inline namespace SPANNER_CLIENT_NS {
 Status MergeChunk(google::protobuf::Value& value,
                   google::protobuf::Value&& chunk);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/merge_chunk_benchmark.cc b/google/cloud/spanner/internal/merge_chunk_benchmark.cc
index 32a0826206ffb..ce50a3827b053 100644
--- a/google/cloud/spanner/internal/merge_chunk_benchmark.cc
+++ b/google/cloud/spanner/internal/merge_chunk_benchmark.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 //
@@ -116,7 +116,7 @@ void BM_MergeChunkListsOfListOfString(benchmark::State& state) {
 BENCHMARK(BM_MergeChunkListsOfListOfString);
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/merge_chunk_test.cc b/google/cloud/spanner/internal/merge_chunk_test.cc
index d2e607716d5a6..d4e7625d306e2 100644
--- a/google/cloud/spanner/internal/merge_chunk_test.cc
+++ b/google/cloud/spanner/internal/merge_chunk_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 using ::google::cloud::testing_util::IsProtoEqual;
 using ::google::cloud::testing_util::StatusIs;
@@ -221,7 +221,7 @@ TEST(MergeChunk, CannotMergeStruct) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/metadata_spanner_stub.cc b/google/cloud/spanner/internal/metadata_spanner_stub.cc
index 7bd54b21b0c6e..ba94e88c38e0b 100644
--- a/google/cloud/spanner/internal/metadata_spanner_stub.cc
+++ b/google/cloud/spanner/internal/metadata_spanner_stub.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace spanner_proto = ::google::spanner::v1;
 
@@ -169,7 +169,7 @@ void MetadataSpannerStub::SetMetadata(grpc::ClientContext& context,
   context.AddMetadata("google-cloud-resource-prefix", resource_prefix_header_);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/metadata_spanner_stub.h b/google/cloud/spanner/internal/metadata_spanner_stub.h
index fad02bf2726c5..1d8179ee9eda7 100644
--- a/google/cloud/spanner/internal/metadata_spanner_stub.h
+++ b/google/cloud/spanner/internal/metadata_spanner_stub.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A SpannerStub that decorates the ClientContext with the right metadata.
@@ -105,7 +105,7 @@ class MetadataSpannerStub : public SpannerStub {
   std::string resource_prefix_header_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/metadata_spanner_stub_test.cc b/google/cloud/spanner/internal/metadata_spanner_stub_test.cc
index fbe851d2aa277..aee6d07e0bc90 100644
--- a/google/cloud/spanner/internal/metadata_spanner_stub_test.cc
+++ b/google/cloud/spanner/internal/metadata_spanner_stub_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsContextMDValid;
@@ -270,7 +270,7 @@ TEST_F(MetadataSpannerStubTest, PartitionRead) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/partial_result_set_reader.h b/google/cloud/spanner/internal/partial_result_set_reader.h
index 08bff2656064c..78c3c7f32752c 100644
--- a/google/cloud/spanner/internal/partial_result_set_reader.h
+++ b/google/cloud/spanner/internal/partial_result_set_reader.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Wrap `grpc::ClientReaderInterface<google::spanner::v1::PartialResultSet>`.
@@ -44,7 +44,7 @@ class PartialResultSetReader {
   virtual Status Finish() = 0;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/partial_result_set_resume.cc b/google/cloud/spanner/internal/partial_result_set_resume.cc
index 77928b27a6dee..1feee35a5f911 100644
--- a/google/cloud/spanner/internal/partial_result_set_resume.cc
+++ b/google/cloud/spanner/internal/partial_result_set_resume.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 void PartialResultSetResume::TryCancel() { child_->TryCancel(); }
 
@@ -53,7 +53,7 @@ Status PartialResultSetResume::Finish() {
   return *last_status_;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/partial_result_set_resume.h b/google/cloud/spanner/internal/partial_result_set_resume.h
index 453a37f5359ef..646f2b357a14d 100644
--- a/google/cloud/spanner/internal/partial_result_set_resume.h
+++ b/google/cloud/spanner/internal/partial_result_set_resume.h
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Create a new PartialResultSetReader given a resume token value.
 using PartialResultSetReaderFactory =
@@ -66,7 +66,7 @@ class PartialResultSetResume : public PartialResultSetReader {
   absl::optional<Status> last_status_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/partial_result_set_resume_test.cc b/google/cloud/spanner/internal/partial_result_set_resume_test.cc
index 587feb1f51ae6..04b90f5a9325d 100644
--- a/google/cloud/spanner/internal/partial_result_set_resume_test.cc
+++ b/google/cloud/spanner/internal/partial_result_set_resume_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace spanner_proto = ::google::spanner::v1;
@@ -296,7 +296,7 @@ TEST(PartialResultSetResume, TooManyTransients) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/partial_result_set_source.cc b/google/cloud/spanner/internal/partial_result_set_source.cc
index ae3c7325f9032..8d3cf2ec2653f 100644
--- a/google/cloud/spanner/internal/partial_result_set_source.cc
+++ b/google/cloud/spanner/internal/partial_result_set_source.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<std::unique_ptr<ResultSourceInterface>> PartialResultSetSource::Create(
     std::unique_ptr<PartialResultSetReader> reader) {
@@ -179,7 +179,7 @@ Status PartialResultSetSource::ReadFromStream() {
   return {};  // OK
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/partial_result_set_source.h b/google/cloud/spanner/internal/partial_result_set_source.h
index e93627ad4a401..08f8ae319a89a 100644
--- a/google/cloud/spanner/internal/partial_result_set_source.h
+++ b/google/cloud/spanner/internal/partial_result_set_source.h
@@ -32,7 +32,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * This class serves as a bridge between the gRPC `PartialResultSet` streaming
@@ -73,7 +73,7 @@ class PartialResultSetSource : public ResultSourceInterface {
   bool finished_ = false;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/partial_result_set_source_test.cc b/google/cloud/spanner/internal/partial_result_set_source_test.cc
index 8e1b30154c576..838f7f60bf6af 100644
--- a/google/cloud/spanner/internal/partial_result_set_source_test.cc
+++ b/google/cloud/spanner/internal/partial_result_set_source_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace spanner_proto = ::google::spanner::v1;
@@ -705,7 +705,7 @@ TEST(PartialResultSetSourceTest, ErrorOnIncompleteRow) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/session.cc b/google/cloud/spanner/internal/session.cc
index 1b6213b180691..9f7495f4f3f2f 100644
--- a/google/cloud/spanner/internal/session.cc
+++ b/google/cloud/spanner/internal/session.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 SessionHolder MakeDissociatedSessionHolder(std::string session_name) {
   return SessionHolder(
@@ -25,7 +25,7 @@ SessionHolder MakeDissociatedSessionHolder(std::string session_name) {
       std::default_delete<Session>());
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/session.h b/google/cloud/spanner/internal/session.h
index 41e2471395d8d..86ae488da637e 100644
--- a/google/cloud/spanner/internal/session.h
+++ b/google/cloud/spanner/internal/session.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A class that represents a Session.
@@ -88,7 +88,7 @@ using SessionHolder = std::shared_ptr<Session>;
  */
 SessionHolder MakeDissociatedSessionHolder(std::string session_name);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/session_pool.cc b/google/cloud/spanner/internal/session_pool.cc
index 8e4a22a8ae030..a555d70c5a6e3 100644
--- a/google/cloud/spanner/internal/session_pool.cc
+++ b/google/cloud/spanner/internal/session_pool.cc
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace spanner_proto = ::google::spanner::v1;
 
@@ -489,7 +489,7 @@ Status SessionPool::HandleBatchCreateSessionsDone(
   return Status();
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/session_pool.h b/google/cloud/spanner/internal/session_pool.h
index 9e5e8ece71af5..5ff95a68b83c0 100644
--- a/google/cloud/spanner/internal/session_pool.h
+++ b/google/cloud/spanner/internal/session_pool.h
@@ -43,7 +43,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct SessionPoolFriendForTest;
 
 // An option for the Clock that the session pool will use. This is an injection
@@ -205,7 +205,7 @@ class SessionPool : public std::enable_shared_from_this<SessionPool> {
   ChannelVec::iterator next_dissociated_stub_channel_;  // GUARDED_BY(mu_)
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/session_pool_test.cc b/google/cloud/spanner/internal/session_pool_test.cc
index b077242c41c9d..93008f932b64e 100644
--- a/google/cloud/spanner/internal/session_pool_test.cc
+++ b/google/cloud/spanner/internal/session_pool_test.cc
@@ -37,7 +37,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::spanner_testing::FakeSteadyClock;
@@ -473,7 +473,7 @@ TEST(SessionPool, SessionRefresh) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/spanner_stub.cc b/google/cloud/spanner/internal/spanner_stub.cc
index e90d4445f93b0..f35ceba020671 100644
--- a/google/cloud/spanner/internal/spanner_stub.cc
+++ b/google/cloud/spanner/internal/spanner_stub.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace spanner_proto = ::google::spanner::v1;
@@ -312,7 +312,7 @@ std::shared_ptr<SpannerStub> CreateDefaultSpannerStub(
   return stub;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/spanner_stub.h b/google/cloud/spanner/internal/spanner_stub.h
index 86894c5e352f9..877e64eb9a4cc 100644
--- a/google/cloud/spanner/internal/spanner_stub.h
+++ b/google/cloud/spanner/internal/spanner_stub.h
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * SpannerStub is a thin stub layer over the Cloud Spanner API to avoid
@@ -125,7 +125,7 @@ class SpannerStub {
 std::shared_ptr<SpannerStub> CreateDefaultSpannerStub(
     spanner::Database const& db, Options const& opts, int channel_id);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/spanner_stub_test.cc b/google/cloud/spanner/internal/spanner_stub_test.cc
index 6d3e34a477ac8..0d3a408a3c29c 100644
--- a/google/cloud/spanner/internal/spanner_stub_test.cc
+++ b/google/cloud/spanner/internal/spanner_stub_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -66,7 +66,7 @@ TEST(SpannerStub, CreateDefaultStubWithLogging) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/status_utils.cc b/google/cloud/spanner/internal/status_utils.cc
index 41c2bcf16aaf6..1e4d663afdc22 100644
--- a/google/cloud/spanner/internal/status_utils.cc
+++ b/google/cloud/spanner/internal/status_utils.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 bool IsSessionNotFound(google::cloud::Status const& status) {
   // "Session not found" in the status message is an API guarantee.
@@ -26,7 +26,7 @@ bool IsSessionNotFound(google::cloud::Status const& status) {
          status.message().find("Session not found") != std::string::npos;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/status_utils.h b/google/cloud/spanner/internal/status_utils.h
index bcab0848a1bf2..70ea412b3d0cc 100644
--- a/google/cloud/spanner/internal/status_utils.h
+++ b/google/cloud/spanner/internal/status_utils.h
@@ -21,12 +21,12 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Determine if `status` represents a "Session not found" error.
 bool IsSessionNotFound(google::cloud::Status const& status);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/status_utils_test.cc b/google/cloud/spanner/internal/status_utils_test.cc
index 5a49316f110ad..aea090a754858 100644
--- a/google/cloud/spanner/internal/status_utils_test.cc
+++ b/google/cloud/spanner/internal/status_utils_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(StatusUtils, SessionNotFound) {
@@ -36,7 +36,7 @@ TEST(StatusUtils, SessionNotFound) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/transaction_impl.cc b/google/cloud/spanner/internal/transaction_impl.cc
index 434953f4b31bb..4053beba364ad 100644
--- a/google/cloud/spanner/internal/transaction_impl.cc
+++ b/google/cloud/spanner/internal/transaction_impl.cc
@@ -17,11 +17,11 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 TransactionImpl::~TransactionImpl() = default;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/transaction_impl.h b/google/cloud/spanner/internal/transaction_impl.h
index 1e041a11117ee..03943fac163a8 100644
--- a/google/cloud/spanner/internal/transaction_impl.h
+++ b/google/cloud/spanner/internal/transaction_impl.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 template <typename Functor>
 using VisitInvokeResult = ::google::cloud::internal::invoke_result_t<
@@ -147,7 +147,7 @@ class TransactionImpl {
   std::int64_t seqno_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/transaction_impl_test.cc b/google/cloud/spanner/internal/transaction_impl_test.cc
index 346067d35287d..2c8e0baf4ed4e 100644
--- a/google/cloud/spanner/internal/transaction_impl_test.cc
+++ b/google/cloud/spanner/internal/transaction_impl_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::spanner::v1::TransactionSelector;
@@ -255,7 +255,7 @@ TEST(InternalTransaction, ReadFailsAndTxnInvalidated) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/tuple_utils.h b/google/cloud/spanner/internal/tuple_utils.h
index 756b816bb47bf..8efd4c2daae0d 100644
--- a/google/cloud/spanner/internal/tuple_utils.h
+++ b/google/cloud/spanner/internal/tuple_utils.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 // The implementation for `IsTuple<T>` (below).
 template <typename T>
@@ -80,7 +80,7 @@ typename std::enable_if<(I < TupleSize<T>::value), void>::type ForEach(
                  std::forward<Args>(args)...);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/internal/tuple_utils_test.cc b/google/cloud/spanner/internal/tuple_utils_test.cc
index 8dbdd69faaa72..359e919ac6658 100644
--- a/google/cloud/spanner/internal/tuple_utils_test.cc
+++ b/google/cloud/spanner/internal/tuple_utils_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::testing::ElementsAre;
 
@@ -68,7 +68,7 @@ TEST(TupleUtils, ForEachMutate) {
   EXPECT_EQ(tup, std::make_tuple(2, 3, 4));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/json.h b/google/cloud/spanner/json.h
index a6ccc8fdc9392..23c9e47c2eade 100644
--- a/google/cloud/spanner/json.h
+++ b/google/cloud/spanner/json.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A simple representation for the Spanner JSON type: a lightweight,
@@ -81,7 +81,7 @@ inline std::ostream& operator<<(std::ostream& os, Json const& json) {
   return os << std::string(json);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/json_test.cc b/google/cloud/spanner/json_test.cc
index 00e01a88b17da..e89c0f88ab4d7 100644
--- a/google/cloud/spanner/json_test.cc
+++ b/google/cloud/spanner/json_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(Json, DefaultCtor) { EXPECT_EQ("null", std::string(Json())); }
@@ -69,7 +69,7 @@ TEST(Json, OutputStreaming) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/keys.cc b/google/cloud/spanner/keys.cc
index adcb73c662a3c..2922f027fcf24 100644
--- a/google/cloud/spanner/keys.cc
+++ b/google/cloud/spanner/keys.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 // Appends the values in the given `key` to the `lv` proto.
 void AppendKey(google::protobuf::ListValue& lv, Key&& key) {
@@ -59,7 +59,7 @@ bool operator==(KeySet const& a, KeySet const& b) {
   return differencer.Compare(a.proto_, b.proto_);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/keys.h b/google/cloud/spanner/keys.h
index 7df598a3eb09c..3df6291460b30 100644
--- a/google/cloud/spanner/keys.h
+++ b/google/cloud/spanner/keys.h
@@ -24,13 +24,13 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct KeySetInternals;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A `Key` is a collection of `Value` objects where the i'th value corresponds
@@ -200,18 +200,18 @@ class KeySet {
   ///@}
 
  private:
-  friend struct spanner_internal::SPANNER_CLIENT_NS::KeySetInternals;
+  friend struct spanner_internal::GOOGLE_CLOUD_CPP_NS::KeySetInternals;
   explicit KeySet(google::spanner::v1::KeySet proto)
       : proto_(std::move(proto)) {}
 
   google::spanner::v1::KeySet proto_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct KeySetInternals {
   static ::google::spanner::v1::KeySet ToProto(spanner::KeySet&& ks) {
     return std::move(ks.proto_);
@@ -230,7 +230,7 @@ inline spanner::KeySet FromProto(::google::spanner::v1::KeySet ks) {
   return KeySetInternals::FromProto(std::move(ks));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/keys_test.cc b/google/cloud/spanner/keys_test.cc
index bc733c69956cb..862be5705c00c 100644
--- a/google/cloud/spanner/keys_test.cc
+++ b/google/cloud/spanner/keys_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -215,7 +215,7 @@ TEST(KeySetTest, RoundTripProtos) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/mocks/mock_database_admin_connection.h b/google/cloud/spanner/mocks/mock_database_admin_connection.h
index 73d0cdcb37b72..47c7c5c44b210 100644
--- a/google/cloud/spanner/mocks/mock_database_admin_connection.h
+++ b/google/cloud/spanner/mocks/mock_database_admin_connection.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_mocks {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A class to mock `google::cloud::spanner::DatabaseAdminConnection`.
@@ -72,7 +72,7 @@ class MockDatabaseAdminConnection
               (ListDatabaseOperationsParams), (override));
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_mocks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/mocks/mock_instance_admin_connection.h b/google/cloud/spanner/mocks/mock_instance_admin_connection.h
index 5252574eed3ab..88c09ffe5f081 100644
--- a/google/cloud/spanner/mocks/mock_instance_admin_connection.h
+++ b/google/cloud/spanner/mocks/mock_instance_admin_connection.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_mocks {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * A class to mock `google::cloud::spanner::InstanceAdminConnection`.
  *
@@ -55,7 +55,7 @@ class MockInstanceAdminConnection
               TestIamPermissions, (TestIamPermissionsParams), (override));
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_mocks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/mocks/mock_spanner_connection.h b/google/cloud/spanner/mocks/mock_spanner_connection.h
index a871d10e571b6..80a98988a9cc1 100644
--- a/google/cloud/spanner/mocks/mock_spanner_connection.h
+++ b/google/cloud/spanner/mocks/mock_spanner_connection.h
@@ -28,7 +28,7 @@ namespace cloud {
 /// Define classes to mock the Cloud Spanner C++ client APIs.
 namespace spanner_mocks {
 /// An inlined versioned namespace to avoid dependency diamonds.
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A class to mock `google::cloud::spanner::Connection`.
@@ -79,7 +79,7 @@ class MockResultSetSource : public spanner_internal::ResultSourceInterface {
               (const, override));
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_mocks
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/mutations.cc b/google/cloud/spanner/mutations.cc
index 0e815b69b9f6e..8baa05c0ca2d2 100644
--- a/google/cloud/spanner/mutations.cc
+++ b/google/cloud/spanner/mutations.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 bool operator==(Mutation const& lhs, Mutation const& rhs) {
   google::protobuf::util::MessageDifferencer diff;
@@ -30,7 +30,7 @@ void PrintTo(Mutation const& m, std::ostream* os) {
   *os << "Mutation={" << m.m_.DebugString() << "}";
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/mutations.h b/google/cloud/spanner/mutations.h
index 7a887c24e5566..429336c7c438e 100644
--- a/google/cloud/spanner/mutations.h
+++ b/google/cloud/spanner/mutations.h
@@ -25,15 +25,15 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 template <typename Op>
 class WriteMutationBuilder;
 class DeleteMutationBuilder;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A wrapper for Cloud Spanner mutations.
@@ -85,8 +85,8 @@ class Mutation {
   google::spanner::v1::Mutation& proto() & { return m_; }
 
   template <typename Op>
-  friend class spanner_internal::SPANNER_CLIENT_NS::WriteMutationBuilder;
-  friend class spanner_internal::SPANNER_CLIENT_NS::DeleteMutationBuilder;
+  friend class spanner_internal::GOOGLE_CLOUD_CPP_NS::WriteMutationBuilder;
+  friend class spanner_internal::GOOGLE_CLOUD_CPP_NS::DeleteMutationBuilder;
   explicit Mutation(google::spanner::v1::Mutation m) : m_(std::move(m)) {}
 
   google::spanner::v1::Mutation m_;
@@ -98,13 +98,13 @@ class Mutation {
  */
 using Mutations = std::vector<Mutation>;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 // This namespace contains implementation details. It is not part of the public
 // API, and subject to change without notice.
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 template <typename Op>
 class WriteMutationBuilder {
@@ -192,11 +192,11 @@ class DeleteMutationBuilder {
   spanner::Mutation m_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A helper class to construct "insert" mutations.
@@ -370,7 +370,7 @@ inline Mutation MakeDeleteMutation(std::string table_name, KeySet keys) {
   return DeleteMutationBuilder(std::move(table_name), std::move(keys)).Build();
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/mutations_test.cc b/google/cloud/spanner/mutations_test.cc
index cc6d0f5e0209d..0bb96398f4d3f 100644
--- a/google/cloud/spanner/mutations_test.cc
+++ b/google/cloud/spanner/mutations_test.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace spanner_proto = ::google::spanner::v1;
@@ -422,7 +422,7 @@ TEST(MutationsTest, FluentDeleteBuilder) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/numeric.cc b/google/cloud/spanner/numeric.cc
index 8f7bd020ad078..89a5c150fd6ae 100644
--- a/google/cloud/spanner/numeric.cc
+++ b/google/cloud/spanner/numeric.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace {
 
@@ -231,11 +231,11 @@ StatusOr<spanner::Numeric> MakeNumeric(std::string s, int exponent) {
   return MakeNumeric(std::move(s));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 constexpr std::size_t Numeric::kIntPrec;
 constexpr std::size_t Numeric::kFracPrec;
@@ -255,7 +255,7 @@ StatusOr<Numeric> MakeNumeric(double d) {
   return spanner_internal::MakeNumeric(std::move(s));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/numeric.h b/google/cloud/spanner/numeric.h
index 582c456747ef1..beff8f71a8a1f 100644
--- a/google/cloud/spanner/numeric.h
+++ b/google/cloud/spanner/numeric.h
@@ -30,14 +30,14 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class Numeric;  // defined below
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 // Internal implementation details that callers should not use.
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 StatusOr<spanner::Numeric> MakeNumeric(std::string s);
 
 // Like `std::to_string`, but also supports Abseil 128-bit integers.
@@ -52,11 +52,11 @@ std::string ToString(absl::uint128 value);
 Status DataLoss(std::string message);
 StatusOr<spanner::Numeric> MakeNumeric(std::string s, int exponent);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A representation of the Spanner NUMERIC type: an exact numeric value with
@@ -132,7 +132,7 @@ class Numeric {
   }
 
  private:
-  friend StatusOr<Numeric> spanner_internal::SPANNER_CLIENT_NS::MakeNumeric(
+  friend StatusOr<Numeric> spanner_internal::GOOGLE_CLOUD_CPP_NS::MakeNumeric(
       std::string s);
   explicit Numeric(std::string rep) : rep_(std::move(rep)) {}
   std::string rep_;  // a valid and canonical NUMERIC representation
@@ -285,7 +285,7 @@ StatusOr<T> ToInteger(  // NOLINT(misc-no-recursion)
 }
 ///@}
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/numeric_benchmark.cc b/google/cloud/spanner/numeric_benchmark.cc
index 4f473f9b755d0..2eccfc9b1f673 100644
--- a/google/cloud/spanner/numeric_benchmark.cc
+++ b/google/cloud/spanner/numeric_benchmark.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 // Run on (96 X 2000.17 MHz CPU s)
@@ -121,7 +121,7 @@ void BM_NumericToInteger(benchmark::State& state) {
 BENCHMARK(BM_NumericToInteger);
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/numeric_test.cc b/google/cloud/spanner/numeric_test.cc
index 862d8364f6c0b..2ad9a254f03a9 100644
--- a/google/cloud/spanner/numeric_test.cc
+++ b/google/cloud/spanner/numeric_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -542,7 +542,7 @@ TEST(Numeric, MakeNumericIntegerScaledFail) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/options.h b/google/cloud/spanner/options.h
index 331e3f8101b02..b6b7fa1e6b061 100644
--- a/google/cloud/spanner/options.h
+++ b/google/cloud/spanner/options.h
@@ -52,7 +52,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Option for `google::cloud::Options` to set a `spanner::RetryPolicy`.
@@ -175,7 +175,7 @@ struct RequestTagOption {
  */
 using RequestOptionList = OptionList<RequestPriorityOption, RequestTagOption>;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/partition_options.cc b/google/cloud/spanner/partition_options.cc
index fcf5b60228096..a8909cc735ab5 100644
--- a/google/cloud/spanner/partition_options.cc
+++ b/google/cloud/spanner/partition_options.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 google::spanner::v1::PartitionOptions ToProto(
     spanner::PartitionOptions const& po) {
@@ -29,7 +29,7 @@ google::spanner::v1::PartitionOptions ToProto(
   return proto;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/partition_options.h b/google/cloud/spanner/partition_options.h
index cf6ac0ef44369..fec8d3fbd921d 100644
--- a/google/cloud/spanner/partition_options.h
+++ b/google/cloud/spanner/partition_options.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Options passed to `Client::PartitionRead` or `Client::PartitionQuery`.
@@ -63,14 +63,14 @@ inline bool operator!=(PartitionOptions const& a, PartitionOptions const& b) {
   return !(a == b);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 // Internal implementation details that callers should not use.
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 google::spanner::v1::PartitionOptions ToProto(spanner::PartitionOptions const&);
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/partition_options_test.cc b/google/cloud/spanner/partition_options_test.cc
index 6a17608dd57f1..6a80c67afcd30 100644
--- a/google/cloud/spanner/partition_options_test.cc
+++ b/google/cloud/spanner/partition_options_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(PartitionOptionsTest, Regular) {
@@ -48,7 +48,7 @@ TEST(PartitionOptionsTest, Proto) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/partitioned_dml_result.h b/google/cloud/spanner/partitioned_dml_result.h
index 754050687e6f4..2f39e018ab51a 100644
--- a/google/cloud/spanner/partitioned_dml_result.h
+++ b/google/cloud/spanner/partitioned_dml_result.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * The result of executing a Partitioned DML query.
@@ -31,7 +31,7 @@ struct PartitionedDmlResult {
   std::int64_t row_count_lower_bound;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/polling_policy.h b/google/cloud/spanner/polling_policy.h
index 45e268e232738..ed55c0b75158a 100644
--- a/google/cloud/spanner/polling_policy.h
+++ b/google/cloud/spanner/polling_policy.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using PollingPolicy = ::google::cloud::PollingPolicy;
 
@@ -33,7 +33,7 @@ template <typename Retry = LimitedTimeRetryPolicy,
 using GenericPollingPolicy =
     ::google::cloud::GenericPollingPolicy<Retry, Backoff>;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/query_options.h b/google/cloud/spanner/query_options.h
index ba665af1967ff..c91d2bcfbabab 100644
--- a/google/cloud/spanner/query_options.h
+++ b/google/cloud/spanner/query_options.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * These QueryOptions allow users to configure features about how their SQL
@@ -113,7 +113,7 @@ class QueryOptions {
   absl::optional<std::string> request_tag_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/query_options_test.cc b/google/cloud/spanner/query_options_test.cc
index ee673250cf6da..53469291bfd28 100644
--- a/google/cloud/spanner/query_options_test.cc
+++ b/google/cloud/spanner/query_options_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(QueryOptionsTest, Values) {
@@ -84,7 +84,7 @@ TEST(QueryOptionsTest, OptimizerStatisticsPackage) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/query_partition.cc b/google/cloud/spanner/query_partition.cc
index 01f0962a44cfb..b35d56c115c25 100644
--- a/google/cloud/spanner/query_partition.cc
+++ b/google/cloud/spanner/query_partition.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 QueryPartition::QueryPartition(std::string transaction_id,
                                std::string transaction_tag,
@@ -98,7 +98,7 @@ StatusOr<QueryPartition> DeserializeQueryPartition(
   return query_partition;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/query_partition.h b/google/cloud/spanner/query_partition.h
index 415987b0f8580..402900c621a88 100644
--- a/google/cloud/spanner/query_partition.h
+++ b/google/cloud/spanner/query_partition.h
@@ -25,13 +25,13 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct QueryPartitionInternals;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Serializes an instance of `QueryPartition` to a string of bytes.
@@ -114,7 +114,7 @@ class QueryPartition {
 
  private:
   friend class QueryPartitionTester;
-  friend struct spanner_internal::SPANNER_CLIENT_NS::QueryPartitionInternals;
+  friend struct spanner_internal::GOOGLE_CLOUD_CPP_NS::QueryPartitionInternals;
   friend StatusOr<std::string> SerializeQueryPartition(
       QueryPartition const& query_partition);
   friend StatusOr<QueryPartition> DeserializeQueryPartition(
@@ -137,12 +137,12 @@ class QueryPartition {
   SqlStatement sql_statement_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 // Internal implementation details that callers should not use.
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 struct QueryPartitionInternals {
   static spanner::QueryPartition MakeQueryPartition(
@@ -178,7 +178,7 @@ inline spanner::Connection::SqlParams MakeSqlParams(
   return QueryPartitionInternals::MakeSqlParams(query_partition);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/query_partition_test.cc b/google/cloud/spanner/query_partition_test.cc
index 2894c2c7ea0b6..a84e692061574 100644
--- a/google/cloud/spanner/query_partition_test.cc
+++ b/google/cloud/spanner/query_partition_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class QueryPartitionTester {
  public:
@@ -162,7 +162,7 @@ TEST(QueryPartitionTest, MakeSqlParams) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/read_options.h b/google/cloud/spanner/read_options.h
index 78a06dbb98b76..f7147513c18bd 100644
--- a/google/cloud/spanner/read_options.h
+++ b/google/cloud/spanner/read_options.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Options passed to `Client::Read` or `Client::PartitionRead`.
 struct ReadOptions {
@@ -62,7 +62,7 @@ inline bool operator!=(ReadOptions const& lhs, ReadOptions const& rhs) {
   return !(lhs == rhs);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/read_options_test.cc b/google/cloud/spanner/read_options_test.cc
index 0a11a5ecd7f18..8bffcd427793b 100644
--- a/google/cloud/spanner/read_options_test.cc
+++ b/google/cloud/spanner/read_options_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(ReadOptionsTest, Equality) {
@@ -51,7 +51,7 @@ TEST(ReadOptionsTest, Equality) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/read_partition.cc b/google/cloud/spanner/read_partition.cc
index 4e742fb615124..ef9a2428bea4a 100644
--- a/google/cloud/spanner/read_partition.cc
+++ b/google/cloud/spanner/read_partition.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 ReadPartition::ReadPartition(std::string transaction_id,
                              std::string transaction_tag,
@@ -117,7 +117,7 @@ StatusOr<ReadPartition> DeserializeReadPartition(
   return ReadPartition(std::move(proto));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/read_partition.h b/google/cloud/spanner/read_partition.h
index 9a587c2cd3a90..41162b1f6e705 100644
--- a/google/cloud/spanner/read_partition.h
+++ b/google/cloud/spanner/read_partition.h
@@ -26,13 +26,13 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct ReadPartitionInternals;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Serializes an instance of `ReadPartition` to a string of bytes.
@@ -117,7 +117,7 @@ class ReadPartition {
 
  private:
   friend class ReadPartitionTester;
-  friend struct spanner_internal::SPANNER_CLIENT_NS::ReadPartitionInternals;
+  friend struct spanner_internal::GOOGLE_CLOUD_CPP_NS::ReadPartitionInternals;
   friend StatusOr<std::string> SerializeReadPartition(
       ReadPartition const& read_partition);
   friend StatusOr<ReadPartition> DeserializeReadPartition(
@@ -143,12 +143,12 @@ class ReadPartition {
   google::spanner::v1::ReadRequest proto_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 // Internal implementation details that callers should not use.
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 struct ReadPartitionInternals {
   static spanner::ReadPartition MakeReadPartition(
@@ -194,7 +194,7 @@ inline spanner::Connection::ReadParams MakeReadParams(
   return ReadPartitionInternals::MakeReadParams(read_partition);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/read_partition_test.cc b/google/cloud/spanner/read_partition_test.cc
index c2f5e27df6719..f7cc33a2e1640 100644
--- a/google/cloud/spanner/read_partition_test.cc
+++ b/google/cloud/spanner/read_partition_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class ReadPartitionTester {
  public:
@@ -194,7 +194,7 @@ TEST(ReadPartitionTest, MakeReadParams) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/request_priority.h b/google/cloud/spanner/request_priority.h
index 6ebb21be26143..a13c1ac6fdc8c 100644
--- a/google/cloud/spanner/request_priority.h
+++ b/google/cloud/spanner/request_priority.h
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 // The relative priority for requests.
 enum class RequestPriority {
@@ -29,7 +29,7 @@ enum class RequestPriority {
   kHigh,
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/results.cc b/google/cloud/spanner/results.cc
index 2526d7aef5747..db6690e705818 100644
--- a/google/cloud/spanner/results.cc
+++ b/google/cloud/spanner/results.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 absl::optional<Timestamp> GetReadTimestamp(
@@ -101,7 +101,7 @@ absl::optional<spanner::ExecutionPlan> ProfileDmlResult::ExecutionPlan() const {
   return GetExecutionPlan(source_);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/results.h b/google/cloud/spanner/results.h
index c21ba96b02805..9e71848eb7fe5 100644
--- a/google/cloud/spanner/results.h
+++ b/google/cloud/spanner/results.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class ResultSourceInterface {
  public:
   virtual ~ResultSourceInterface() = default;
@@ -38,11 +38,11 @@ class ResultSourceInterface {
   virtual absl::optional<google::spanner::v1::ResultSetStats> Stats() const = 0;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Contains a hierarchical representation of the operations the database server
@@ -249,7 +249,7 @@ class ProfileDmlResult {
  private:
   std::unique_ptr<spanner_internal::ResultSourceInterface> source_;
 };
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/results_test.cc b/google/cloud/spanner/results_test.cc
index bf384a6820980..b91a9193ae3d1 100644
--- a/google/cloud/spanner/results_test.cc
+++ b/google/cloud/spanner/results_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 namespace spanner_proto = ::google::spanner::v1;
@@ -246,7 +246,7 @@ TEST(ProfileDmlResult, ExecutionStats) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/retry_policy.h b/google/cloud/spanner/retry_policy.h
index 7d5d085bc1b90..7c6f0ac5c766a 100644
--- a/google/cloud/spanner/retry_policy.h
+++ b/google/cloud/spanner/retry_policy.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Define the gRPC status code semantics for retrying requests.
 struct SafeGrpcRetry {
@@ -67,11 +67,11 @@ struct SafeTransactionRerun {
     return !IsOk(status) && !IsTransientFailure(status);
   }
 };
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// The base class for retry policies.
 using RetryPolicy = ::google::cloud::internal::TraitBasedRetryPolicy<
@@ -101,7 +101,7 @@ using LimitedErrorCountTransactionRerunPolicy =
     google::cloud::internal::LimitedErrorCountRetryPolicy<
         spanner_internal::SafeTransactionRerun>;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/retry_policy_test.cc b/google/cloud/spanner/retry_policy_test.cc
index 564980cfaedc2..0c1cec1e6a4a4 100644
--- a/google/cloud/spanner/retry_policy_test.cc
+++ b/google/cloud/spanner/retry_policy_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(RetryPolicyTest, PermanentFailure) {
@@ -51,7 +51,7 @@ TEST(TransactionRerunPolicyTest, PermanentFailure) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/row.cc b/google/cloud/spanner/row.cc
index 9bbcc1b0ccbf0..a72c75301b227 100644
--- a/google/cloud/spanner/row.cc
+++ b/google/cloud/spanner/row.cc
@@ -23,16 +23,16 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 spanner::Row MakeRow(std::vector<spanner::Value> values,
                      std::shared_ptr<std::vector<std::string> const> columns) {
   return spanner::Row(std::move(values), std::move(columns));
 }
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 Row MakeTestRow(std::vector<std::pair<std::string, Value>> pairs) {
   auto values = std::vector<Value>{};
   auto columns = std::make_shared<std::vector<std::string>>();
@@ -113,7 +113,7 @@ bool operator!=(RowStreamIterator const& a, RowStreamIterator const& b) {
   return !(a == b);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/row.h b/google/cloud/spanner/row.h
index 32ff080d7f8a3..dfca38d58dc30 100644
--- a/google/cloud/spanner/row.h
+++ b/google/cloud/spanner/row.h
@@ -32,20 +32,20 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class Row;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 spanner::Row MakeRow(std::vector<spanner::Value>,
                      std::shared_ptr<std::vector<std::string> const>);
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A `Row` is a sequence of columns each with a name and an associated `Value`.
@@ -173,7 +173,7 @@ class Row {
   ///@}
 
  private:
-  friend Row spanner_internal::SPANNER_CLIENT_NS::MakeRow(
+  friend Row spanner_internal::GOOGLE_CLOUD_CPP_NS::MakeRow(
       std::vector<spanner::Value>,
       std::shared_ptr<std::vector<std::string> const>);
   struct ExtractValue {
@@ -477,7 +477,7 @@ auto GetSingularRow(RowRange&& range) -> typename std::decay<
   return row;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/row_benchmark.cc b/google/cloud/spanner/row_benchmark.cc
index fa7665162be29..93381f57a343e 100644
--- a/google/cloud/spanner/row_benchmark.cc
+++ b/google/cloud/spanner/row_benchmark.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 // Run on (6 X 2300 MHz CPU s)
@@ -59,7 +59,7 @@ void BM_RowGetByColumnName(benchmark::State& state) {
 BENCHMARK(BM_RowGetByColumnName);
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/row_test.cc b/google/cloud/spanner/row_test.cc
index 7cf293fd0641c..33a9986a2f1f8 100644
--- a/google/cloud/spanner/row_test.cc
+++ b/google/cloud/spanner/row_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -544,7 +544,7 @@ TEST(GetSingularRow, TupleStreamTooManyRows) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/session_pool_options.h b/google/cloud/spanner/session_pool_options.h
index b040419d7b673..2635bedc3a0a7 100644
--- a/google/cloud/spanner/session_pool_options.h
+++ b/google/cloud/spanner/session_pool_options.h
@@ -27,19 +27,19 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class SessionPoolOptions;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 Options MakeOptions(spanner::SessionPoolOptions);
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Controls the session pool maintained by a `spanner::Client`.
@@ -168,15 +168,15 @@ class SessionPoolOptions {
   Options opts_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 inline Options MakeOptions(spanner::SessionPoolOptions old) {
   return std::move(old.opts_);
 }
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 }  // namespace cloud
diff --git a/google/cloud/spanner/session_pool_options_test.cc b/google/cloud/spanner/session_pool_options_test.cc
index 2eca445e77f16..a95316f9d162f 100644
--- a/google/cloud/spanner/session_pool_options_test.cc
+++ b/google/cloud/spanner/session_pool_options_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(SessionPoolOptionsTest, MinSessions) {
@@ -78,7 +78,7 @@ TEST(SessionPoolOptionsTest, MakeOptions) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/spanner_version_test.cc b/google/cloud/spanner/spanner_version_test.cc
index 5f4aa441fdfef..3ea3ff4134fe5 100644
--- a/google/cloud/spanner/spanner_version_test.cc
+++ b/google/cloud/spanner/spanner_version_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 using ::testing::HasSubstr;
 using ::testing::Not;
 using ::testing::StartsWith;
@@ -51,7 +51,7 @@ TEST(SpannerVersionTest, NoBuildInfoInRelease) {
   EXPECT_THAT(VersionString(), Not(HasSubstr("+")));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/sql_statement.cc b/google/cloud/spanner/sql_statement.cc
index 6b96c49cd7ee0..a4de4a47b2241 100644
--- a/google/cloud/spanner/sql_statement.cc
+++ b/google/cloud/spanner/sql_statement.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 SqlStatementProto SqlStatementInternals::ToProto(spanner::SqlStatement s) {
   ::google::spanner::v1::ExecuteBatchDmlRequest::Statement statement_proto;
   statement_proto.set_sql(std::move(s.statement_));
@@ -33,11 +33,11 @@ SqlStatementProto SqlStatementInternals::ToProto(spanner::SqlStatement s) {
   }
   return statement_proto;
 }
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::vector<std::string> SqlStatement::ParameterNames() const {
   std::vector<std::string> keys;
@@ -65,7 +65,7 @@ std::ostream& operator<<(std::ostream& os, SqlStatement const& stmt) {
   return os;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/sql_statement.h b/google/cloud/spanner/sql_statement.h
index 14080204a7252..7719aa9a48968 100644
--- a/google/cloud/spanner/sql_statement.h
+++ b/google/cloud/spanner/sql_statement.h
@@ -26,13 +26,13 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct SqlStatementInternals;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Represents a potentially parameterized SQL statement.
  *
@@ -108,18 +108,18 @@ class SqlStatement {
   friend std::ostream& operator<<(std::ostream& os, SqlStatement const& stmt);
 
  private:
-  friend struct spanner_internal::SPANNER_CLIENT_NS::SqlStatementInternals;
+  friend struct spanner_internal::GOOGLE_CLOUD_CPP_NS::SqlStatementInternals;
 
   std::string statement_;
   ParamType params_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 // Internal implementation details that callers should not use.
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // Use this proto type because it conveniently wraps all three attributes
 // required to represent a SQL statement.
 using SqlStatementProto =
@@ -132,7 +132,7 @@ struct SqlStatementInternals {
 inline SqlStatementProto ToProto(spanner::SqlStatement s) {
   return SqlStatementInternals::ToProto(std::move(s));
 }
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/sql_statement_test.cc b/google/cloud/spanner/sql_statement_test.cc
index 82ae9e2d7678d..80c5c05f22383 100644
--- a/google/cloud/spanner/sql_statement_test.cc
+++ b/google/cloud/spanner/sql_statement_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsProtoEqual;
@@ -164,7 +164,7 @@ TEST(SqlStatementTest, ToProtoWithParams) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/cleanup_stale_databases.cc b/google/cloud/spanner/testing/cleanup_stale_databases.cc
index 500dc9b039a20..e7b0585e8cfbe 100644
--- a/google/cloud/spanner/testing/cleanup_stale_databases.cc
+++ b/google/cloud/spanner/testing/cleanup_stale_databases.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Status CleanupStaleDatabases(
     google::cloud::spanner_admin::DatabaseAdminClient admin_client,
@@ -48,7 +48,7 @@ Status CleanupStaleDatabases(
   return {};
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/cleanup_stale_databases.h b/google/cloud/spanner/testing/cleanup_stale_databases.h
index 42be33ecd0be8..bd1dbd462f058 100644
--- a/google/cloud/spanner/testing/cleanup_stale_databases.h
+++ b/google/cloud/spanner/testing/cleanup_stale_databases.h
@@ -23,14 +23,14 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Status CleanupStaleDatabases(
     google::cloud::spanner_admin::DatabaseAdminClient admin_client,
     std::string const& project_id, std::string const& instance_id,
     std::chrono::system_clock::time_point tp);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/cleanup_stale_databases_test.cc b/google/cloud/spanner/testing/cleanup_stale_databases_test.cc
index 68c8af58484e2..d6d33e4448fdb 100644
--- a/google/cloud/spanner/testing/cleanup_stale_databases_test.cc
+++ b/google/cloud/spanner/testing/cleanup_stale_databases_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::spanner_admin_mocks::MockDatabaseAdminConnection;
@@ -150,7 +150,7 @@ TEST(CleanupStaleDatabases, RemovesMatching) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/cleanup_stale_instances.cc b/google/cloud/spanner/testing/cleanup_stale_instances.cc
index 0f16e744f880d..cb797bd3d7cb6 100644
--- a/google/cloud/spanner/testing/cleanup_stale_instances.cc
+++ b/google/cloud/spanner/testing/cleanup_stale_instances.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 Status CleanupStaleInstances(std::string const& project_id,
                              std::regex const& instance_name_regex) {
@@ -68,7 +68,7 @@ Status CleanupStaleInstances(std::string const& project_id,
   return Status();
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/cleanup_stale_instances.h b/google/cloud/spanner/testing/cleanup_stale_instances.h
index 570cf4ef29faf..93a5529cda387 100644
--- a/google/cloud/spanner/testing/cleanup_stale_instances.h
+++ b/google/cloud/spanner/testing/cleanup_stale_instances.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Delete any instances (and their backups) within the project @p project_id
@@ -36,7 +36,7 @@ inline namespace SPANNER_CLIENT_NS {
 Status CleanupStaleInstances(std::string const& project_id,
                              std::regex const& instance_name_regex);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/database_integration_test.cc b/google/cloud/spanner/testing/database_integration_test.cc
index 94d8799b91b23..60831c28f7c55 100644
--- a/google/cloud/spanner/testing/database_integration_test.cc
+++ b/google/cloud/spanner/testing/database_integration_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::testing_util::IsOk;
 
@@ -147,7 +147,7 @@ void DatabaseIntegrationTest::TearDownTestSuite() {
   generator_ = nullptr;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/database_integration_test.h b/google/cloud/spanner/testing/database_integration_test.h
index 8592543d9a4ad..be6c31ab068c3 100644
--- a/google/cloud/spanner/testing/database_integration_test.h
+++ b/google/cloud/spanner/testing/database_integration_test.h
@@ -26,7 +26,7 @@ namespace cloud {
 /// Helper types and functions used in Cloud Spanner C++ client library tests.
 namespace spanner_testing {
 /// An inlined, versioned namespace for the testing helpers.
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class DatabaseIntegrationTest
     : public ::google::cloud::testing_util::IntegrationTest {
@@ -41,7 +41,7 @@ class DatabaseIntegrationTest
   static google::cloud::internal::DefaultPRNG* generator_;
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/fake_clock.h b/google/cloud/spanner/testing/fake_clock.h
index ee72340917117..a2c5a9bd7d6a9 100644
--- a/google/cloud/spanner/testing/fake_clock.h
+++ b/google/cloud/spanner/testing/fake_clock.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A fake clock intended for use in tests.
@@ -64,7 +64,7 @@ using FakeSteadyClock = FakeClock<google::cloud::spanner_internal::SteadyClock>;
 
 using FakeSystemClock = FakeClock<google::cloud::spanner_internal::SystemClock>;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/instance_location.cc b/google/cloud/spanner/testing/instance_location.cc
index 197b4c697bf33..45653f8753c37 100644
--- a/google/cloud/spanner/testing/instance_location.cc
+++ b/google/cloud/spanner/testing/instance_location.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<std::string> InstanceLocation(spanner::Instance const& in) {
   spanner_admin::InstanceAdminClient client(
@@ -34,7 +34,7 @@ StatusOr<std::string> InstanceLocation(spanner::Instance const& in) {
                 in.FullName() + ": No default_leader_location for replicas");
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/instance_location.h b/google/cloud/spanner/testing/instance_location.h
index 3097be40d4aca..5a38b5c690098 100644
--- a/google/cloud/spanner/testing/instance_location.h
+++ b/google/cloud/spanner/testing/instance_location.h
@@ -23,14 +23,14 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Return the location for the instance @p in.
  */
 StatusOr<std::string> InstanceLocation(spanner::Instance const& in);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/matchers.h b/google/cloud/spanner/testing/matchers.h
index 228b7431052aa..049d1a86c0675 100644
--- a/google/cloud/spanner/testing/matchers.h
+++ b/google/cloud/spanner/testing/matchers.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Verifies a `Transaction` has the expected Session and ID/tag.
 MATCHER_P3(
@@ -66,7 +66,7 @@ MATCHER_P3(
       });
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/mock_database_admin_stub.h b/google/cloud/spanner/testing/mock_database_admin_stub.h
index 56ab785ad3c7c..7b9d5bb9bc1f7 100644
--- a/google/cloud/spanner/testing/mock_database_admin_stub.h
+++ b/google/cloud/spanner/testing/mock_database_admin_stub.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class MockDatabaseAdminStub
     : public google::cloud::spanner_internal::DatabaseAdminStub {
@@ -146,7 +146,7 @@ class MockDatabaseAdminStub
               (override));
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/mock_instance_admin_stub.h b/google/cloud/spanner/testing/mock_instance_admin_stub.h
index 4bcc19fdb500a..24422fcd085ff 100644
--- a/google/cloud/spanner/testing/mock_instance_admin_stub.h
+++ b/google/cloud/spanner/testing/mock_instance_admin_stub.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class MockInstanceAdminStub
     : public google::cloud::spanner_internal::InstanceAdminStub {
@@ -91,7 +91,7 @@ class MockInstanceAdminStub
               (override));
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/mock_partial_result_set_reader.h b/google/cloud/spanner/testing/mock_partial_result_set_reader.h
index 762a185ca47bf..4aac8677a15ca 100644
--- a/google/cloud/spanner/testing/mock_partial_result_set_reader.h
+++ b/google/cloud/spanner/testing/mock_partial_result_set_reader.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class MockPartialResultSetReader
     : public spanner_internal::PartialResultSetReader {
@@ -33,7 +33,7 @@ class MockPartialResultSetReader
   MOCK_METHOD(Status, Finish, (), (override));
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/mock_spanner_stub.h b/google/cloud/spanner/testing/mock_spanner_stub.h
index 3706564349e69..106ef172ed2e7 100644
--- a/google/cloud/spanner/testing/mock_spanner_stub.h
+++ b/google/cloud/spanner/testing/mock_spanner_stub.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 class MockSpannerStub : public google::cloud::spanner_internal::SpannerStub {
  public:
@@ -130,7 +130,7 @@ class MockSpannerStub : public google::cloud::spanner_internal::SpannerStub {
               (override));
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/pick_instance_config.cc b/google/cloud/spanner/testing/pick_instance_config.cc
index a076d43e45868..68fcdbeb3736c 100644
--- a/google/cloud/spanner/testing/pick_instance_config.cc
+++ b/google/cloud/spanner/testing/pick_instance_config.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string PickInstanceConfig(
     std::string const& project_id, std::regex const& filter_regex,
@@ -52,7 +52,7 @@ std::string PickInstanceConfig(
   return instance_config_name;
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/pick_instance_config.h b/google/cloud/spanner/testing/pick_instance_config.h
index e488c86dacdcf..4326d2c1f2b02 100644
--- a/google/cloud/spanner/testing/pick_instance_config.h
+++ b/google/cloud/spanner/testing/pick_instance_config.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Pick one instance_config from a list given a PRNG generator, project_id,
 /// and a regex for filtering, if none matches the filter, it will return the
@@ -32,7 +32,7 @@ std::string PickInstanceConfig(std::string const& project_id,
                                std::regex const& filter_regex,
                                google::cloud::internal::DefaultPRNG& generator);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/pick_random_instance.cc b/google/cloud/spanner/testing/pick_random_instance.cc
index 8177acbb5fd24..9a71d4d9215ef 100644
--- a/google/cloud/spanner/testing/pick_random_instance.cc
+++ b/google/cloud/spanner/testing/pick_random_instance.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 StatusOr<std::string> PickRandomInstance(
     google::cloud::internal::DefaultPRNG& generator,
@@ -81,7 +81,7 @@ StatusOr<std::string> PickRandomInstance(
   return instance_ids[random_index(generator)];
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/pick_random_instance.h b/google/cloud/spanner/testing/pick_random_instance.h
index f790157afbed0..8f7d3eeeae947 100644
--- a/google/cloud/spanner/testing/pick_random_instance.h
+++ b/google/cloud/spanner/testing/pick_random_instance.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Select one of the instances in @p project_id to run tests on.
@@ -34,7 +34,7 @@ StatusOr<std::string> PickRandomInstance(
     google::cloud::internal::DefaultPRNG& generator,
     std::string const& project_id, std::string const& filter = "");
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/random_backup_name.cc b/google/cloud/spanner/testing/random_backup_name.cc
index a15ee51e5afc8..3111ba98bf53b 100644
--- a/google/cloud/spanner/testing/random_backup_name.cc
+++ b/google/cloud/spanner/testing/random_backup_name.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::string RandomBackupName(google::cloud::internal::DefaultPRNG& generator) {
   // A backup ID must be between 2 and 60 characters, fitting the regular
   // expression `[a-z][a-z0-9_\-]*[a-z0-9]`
@@ -31,7 +31,7 @@ std::string RandomBackupName(google::cloud::internal::DefaultPRNG& generator) {
              generator, 1, "abcdefghijlkmnopqrstuvwxyz0123456789");
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/random_backup_name.h b/google/cloud/spanner/testing/random_backup_name.h
index c04493ba4830a..c67cf52e7fe8f 100644
--- a/google/cloud/spanner/testing/random_backup_name.h
+++ b/google/cloud/spanner/testing/random_backup_name.h
@@ -22,12 +22,12 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Create a random backup name given a PRNG generator.
 std::string RandomBackupName(google::cloud::internal::DefaultPRNG& generator);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/random_database_name.cc b/google/cloud/spanner/testing/random_database_name.cc
index 9b48bb269c521..c5b3904e75ab4 100644
--- a/google/cloud/spanner/testing/random_database_name.cc
+++ b/google/cloud/spanner/testing/random_database_name.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string RandomDatabasePrefixRegex() {
   return R"re(^db-\d{4}-\d{2}-\d{2}-.*$)re";
@@ -43,7 +43,7 @@ std::string RandomDatabaseName(google::cloud::internal::DefaultPRNG& generator,
              generator, 1, "abcdefghijlkmnopqrstuvwxyz0123456789");
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/random_database_name.h b/google/cloud/spanner/testing/random_database_name.h
index e186e169dc080..ede22e6fd43d5 100644
--- a/google/cloud/spanner/testing/random_database_name.h
+++ b/google/cloud/spanner/testing/random_database_name.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Create a random database name given a PRNG generator.
 std::string RandomDatabaseName(google::cloud::internal::DefaultPRNG& generator,
@@ -37,7 +37,7 @@ std::string RandomDatabasePrefixRegex();
 // The prefix for databases created on the (UTC) day at @p tp.
 std::string RandomDatabasePrefix(std::chrono::system_clock::time_point tp);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/random_database_name_test.cc b/google/cloud/spanner/testing/random_database_name_test.cc
index 554c72c3e8eaa..b3cd9601090ae 100644
--- a/google/cloud/spanner/testing/random_database_name_test.cc
+++ b/google/cloud/spanner/testing/random_database_name_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::StartsWith;
@@ -49,7 +49,7 @@ TEST(RandomDatabaseNameTest, RandomNameHasPrefix) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/random_instance_name.cc b/google/cloud/spanner/testing/random_instance_name.cc
index 2f2e3cd34c5ac..9c3849d7fdeb9 100644
--- a/google/cloud/spanner/testing/random_instance_name.cc
+++ b/google/cloud/spanner/testing/random_instance_name.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Generate a random instance name for InstanceAdminClient CRUD tests.
@@ -40,7 +40,7 @@ std::string RandomInstanceName(
                                          "abcdefghijlkmnopqrstuvwxyz");
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/testing/random_instance_name.h b/google/cloud/spanner/testing/random_instance_name.h
index 24df05893fed0..36f15953b4c0a 100644
--- a/google/cloud/spanner/testing/random_instance_name.h
+++ b/google/cloud/spanner/testing/random_instance_name.h
@@ -22,12 +22,12 @@
 namespace google {
 namespace cloud {
 namespace spanner_testing {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Create a random instance name given a PRNG generator.
 std::string RandomInstanceName(google::cloud::internal::DefaultPRNG& generator);
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_testing
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/timestamp.cc b/google/cloud/spanner/timestamp.cc
index f8cafa63b3189..d025d62e7341c 100644
--- a/google/cloud/spanner/timestamp.cc
+++ b/google/cloud/spanner/timestamp.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace {
 
@@ -84,11 +84,11 @@ std::ostream& operator<<(std::ostream& os, Timestamp ts) {
   return os << spanner_internal::TimestampToRFC3339(ts);
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace {
 
@@ -118,7 +118,7 @@ std::string TimestampToRFC3339(spanner::Timestamp ts) {
   return absl::FormatTime(kFormatSpec, t, absl::UTCTimeZone());
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/timestamp.h b/google/cloud/spanner/timestamp.h
index e239ff6a57e91..127595304b700 100644
--- a/google/cloud/spanner/timestamp.h
+++ b/google/cloud/spanner/timestamp.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Convenience alias. `std::chrono::sys_time` since C++20.
@@ -197,14 +197,14 @@ struct CommitTimestamp {
   friend bool operator!=(CommitTimestamp, CommitTimestamp) { return false; }
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 StatusOr<spanner::Timestamp> TimestampFromRFC3339(std::string const&);
 std::string TimestampToRFC3339(spanner::Timestamp);
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 }  // namespace cloud
diff --git a/google/cloud/spanner/timestamp_test.cc b/google/cloud/spanner/timestamp_test.cc
index 5e64b9b733053..5adab185882ae 100644
--- a/google/cloud/spanner/timestamp_test.cc
+++ b/google/cloud/spanner/timestamp_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -554,7 +554,7 @@ TEST(Timestamp, FromAbslTimeOverflow) {  // i.e., `MakeTimestamp(absl::Time)`
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/tracing_options.h b/google/cloud/spanner/tracing_options.h
index f0e67609fd383..ecbb1d7dc0a53 100644
--- a/google/cloud/spanner/tracing_options.h
+++ b/google/cloud/spanner/tracing_options.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * The configuration parameters for RPC/protobuf tracing.
@@ -33,7 +33,7 @@ inline namespace SPANNER_CLIENT_NS {
  */
 using TracingOptions = ::google::cloud::TracingOptions;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/transaction.cc b/google/cloud/spanner/transaction.cc
index ba190e7b771bd..aa75b1e9e3d1a 100644
--- a/google/cloud/spanner/transaction.cc
+++ b/google/cloud/spanner/transaction.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace {
 
@@ -131,11 +131,11 @@ Transaction::Transaction(std::string session_id, std::string transaction_id,
 
 Transaction::~Transaction() = default;
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 spanner::Transaction TransactionInternals::MakeTransactionFromIds(
     std::string session_id, std::string transaction_id,
@@ -144,7 +144,7 @@ spanner::Transaction TransactionInternals::MakeTransactionFromIds(
                               std::move(transaction_tag));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/transaction.h b/google/cloud/spanner/transaction.h
index 7a699cecf3d20..3beb6ffdd4c43 100644
--- a/google/cloud/spanner/transaction.h
+++ b/google/cloud/spanner/transaction.h
@@ -27,13 +27,13 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct TransactionInternals;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * The representation of a Cloud Spanner transaction.
@@ -161,7 +161,7 @@ class Transaction {
 
  private:
   // Friendship for access by internal helpers.
-  friend struct spanner_internal::SPANNER_CLIENT_NS::TransactionInternals;
+  friend struct spanner_internal::GOOGLE_CLOUD_CPP_NS::TransactionInternals;
 
   // Construction of a single-use transaction.
   explicit Transaction(SingleUseOptions opts);
@@ -203,11 +203,11 @@ inline Transaction MakeReadWriteTransaction(
   return Transaction(txn, std::move(opts));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 struct TransactionInternals {
   template <typename T>
@@ -254,7 +254,7 @@ inline spanner::Transaction MakeTransactionFromIds(
       std::move(transaction_tag));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/transaction_test.cc b/google/cloud/spanner/transaction_test.cc
index 0f4e637d0cb2c..ad3b7d4926897 100644
--- a/google/cloud/spanner/transaction_test.cc
+++ b/google/cloud/spanner/transaction_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::IsEmpty;
@@ -131,7 +131,7 @@ TEST(Transaction, SessionAffinity) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/update_instance_request_builder.h b/google/cloud/spanner/update_instance_request_builder.h
index 18a382f2e3e16..c1f90840bd28c 100644
--- a/google/cloud/spanner/update_instance_request_builder.h
+++ b/google/cloud/spanner/update_instance_request_builder.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * UpdateInstanceRequestBuilder is a builder class for
@@ -165,7 +165,7 @@ class UpdateInstanceRequestBuilder {
   }
 };
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/update_instance_request_builder_test.cc b/google/cloud/spanner/update_instance_request_builder_test.cc
index ff406b2b1bf8a..a3b5050387b89 100644
--- a/google/cloud/spanner/update_instance_request_builder_test.cc
+++ b/google/cloud/spanner/update_instance_request_builder_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 TEST(UpdateInstanceRequestBuilder, Constructors) {
   Instance in(Project("test-project"), "test-instance");
@@ -154,7 +154,7 @@ TEST(UpdateInstanceRequestBuilder, SetLabelsRvalueReference) {
       "labels", req.field_mask()));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/value.cc b/google/cloud/spanner/value.cc
index 635215a487e56..884418fed6620 100644
--- a/google/cloud/spanner/value.cc
+++ b/google/cloud/spanner/value.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace {
 
@@ -527,7 +527,7 @@ StatusOr<absl::CivilDay> Value::GetValue(absl::CivilDay,
                 s + ": Failed to match RFC3339 full-date");
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/value.h b/google/cloud/spanner/value.h
index 82a7ae19d3a44..f8f0dc3aa1ecd 100644
--- a/google/cloud/spanner/value.h
+++ b/google/cloud/spanner/value.h
@@ -40,13 +40,13 @@
 namespace google {
 namespace cloud {
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct ValueInternals;
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * The Value class represents a type-safe, nullable Spanner value.
@@ -648,7 +648,7 @@ class Value {
   Value(google::spanner::v1::Type t, google::protobuf::Value v)
       : type_(std::move(t)), value_(std::move(v)) {}
 
-  friend struct spanner_internal::SPANNER_CLIENT_NS::ValueInternals;
+  friend struct spanner_internal::GOOGLE_CLOUD_CPP_NS::ValueInternals;
 
   google::spanner::v1::Type type_;
   google::protobuf::Value value_;
@@ -666,11 +666,11 @@ Value MakeNullValue() {
   return Value(absl::optional<T>{});
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 
 namespace spanner_internal {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 struct ValueInternals {
   static spanner::Value FromProto(google::spanner::v1::Type t,
@@ -694,7 +694,7 @@ inline std::pair<google::spanner::v1::Type, google::protobuf::Value> ToProto(
   return ValueInternals::ToProto(std::move(v));
 }
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner_internal
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/value_test.cc b/google/cloud/spanner/value_test.cc
index f59b61561054d..0c41ca6b5893f 100644
--- a/google/cloud/spanner/value_test.cc
+++ b/google/cloud/spanner/value_test.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -1293,7 +1293,7 @@ TEST(Value, OutputStreamMatchesT) {
 }
 
 }  // namespace
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/version.cc b/google/cloud/spanner/version.cc
index be0ee21471cdc..bb327dfe9b598 100644
--- a/google/cloud/spanner/version.cc
+++ b/google/cloud/spanner/version.cc
@@ -19,9 +19,9 @@
 namespace google {
 namespace cloud {
 namespace spanner {
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::string VersionString() { return ::google::cloud::version_string(); }
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/spanner/version.h b/google/cloud/spanner/version.h
index 7fee75b37d083..1ebb91bee112f 100644
--- a/google/cloud/spanner/version.h
+++ b/google/cloud/spanner/version.h
@@ -27,6 +27,9 @@
       " Please use google::cloud::spanner_admin::" name                     \
       " instead. See GitHub issue #7356 for more information.")
 
+// This preprocessor symbol is deprecated and should never be used anywhere. It
+// exists solely for backward compatibility to avoid breaking anyone who may
+// have been using it.
 #define SPANNER_CLIENT_NS GOOGLE_CLOUD_CPP_NS
 
 namespace google {
@@ -47,7 +50,7 @@ namespace spanner {
  * `spanner::Foo` in their source, but the symbols are versioned, i.e., the
  * symbol becomes `spanner::v1::Foo`.
  */
-inline namespace SPANNER_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * The Cloud spanner C++ Client major version.
  */
@@ -69,7 +72,7 @@ int constexpr Version() { return google::cloud::version(); }
 /// The version as a string, in MAJOR.MINOR.PATCH+gitrev format.
 std::string VersionString();
 
-}  // namespace SPANNER_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace spanner
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/auto_finalize.cc b/google/cloud/storage/auto_finalize.cc
index 67a92bd5886e3..b04c553c3a028 100644
--- a/google/cloud/storage/auto_finalize.cc
+++ b/google/cloud/storage/auto_finalize.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::ostream& operator<<(std::ostream& os, AutoFinalize const& rhs) {
   auto const* value =
@@ -26,7 +26,7 @@ std::ostream& operator<<(std::ostream& os, AutoFinalize const& rhs) {
   return os << AutoFinalize::name() << "=" << value;
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/auto_finalize.h b/google/cloud/storage/auto_finalize.h
index fa65589690621..7e41970d89f4f 100644
--- a/google/cloud/storage/auto_finalize.h
+++ b/google/cloud/storage/auto_finalize.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 enum class AutoFinalizeConfig {
   kDisabled,
@@ -57,7 +57,7 @@ inline AutoFinalize AutoFinalizeDisabled() {
 
 std::ostream& operator<<(std::ostream& os, AutoFinalize const& rhs);
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/auto_finalize_test.cc b/google/cloud/storage/auto_finalize_test.cc
index 0c9efdf5000a0..609794a4639cb 100644
--- a/google/cloud/storage/auto_finalize_test.cc
+++ b/google/cloud/storage/auto_finalize_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(AutoFinalizeTest, Default) {
@@ -50,7 +50,7 @@ TEST(AutoFinalizeTest, Disabled) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/bucket_access_control.cc b/google/cloud/storage/bucket_access_control.cc
index 152a091074e47..923cd49fbbb33 100644
--- a/google/cloud/storage/bucket_access_control.cc
+++ b/google/cloud/storage/bucket_access_control.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 bool operator==(BucketAccessControl const& lhs,
                 BucketAccessControl const& rhs) {
   return *static_cast<internal::AccessControlCommon const*>(&lhs) == rhs;
@@ -39,7 +39,7 @@ std::ostream& operator<<(std::ostream& os, BucketAccessControl const& rhs) {
   return os << ", role=" << rhs.role() << ", self_link=" << rhs.self_link()
             << "}";
 }
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/bucket_access_control.h b/google/cloud/storage/bucket_access_control.h
index 7d709c30f95f4..63e6ec1a468c2 100644
--- a/google/cloud/storage/bucket_access_control.h
+++ b/google/cloud/storage/bucket_access_control.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct BucketAccessControlParser;
 }  // namespace internal
@@ -131,7 +131,7 @@ class BucketAccessControlPatchBuilder {
   internal::PatchBuilder impl_;
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/bucket_access_control_test.cc b/google/cloud/storage/bucket_access_control_test.cc
index c767baff75b12..ddd69b02d272b 100644
--- a/google/cloud/storage/bucket_access_control_test.cc
+++ b/google/cloud/storage/bucket_access_control_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 /// @test Verify that the IOStream operator works as expected.
@@ -97,7 +97,7 @@ TEST(BucketAccessControlTest, Compare) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/bucket_metadata.cc b/google/cloud/storage/bucket_metadata.cc
index b15f56f156adc..d0cb3ba88d990 100644
--- a/google/cloud/storage/bucket_metadata.cc
+++ b/google/cloud/storage/bucket_metadata.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 absl::optional<std::string> const& NormalizePap(
     absl::optional<std::string> const& pap) {
@@ -517,7 +517,7 @@ BucketMetadataPatchBuilder& BucketMetadataPatchBuilder::ResetWebsite() {
   return *this;
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/bucket_metadata.h b/google/cloud/storage/bucket_metadata.h
index d92d98c2d1b71..d84919f129dd4 100644
--- a/google/cloud/storage/bucket_metadata.h
+++ b/google/cloud/storage/bucket_metadata.h
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct BucketMetadataParser;
 class GrpcClient;
@@ -1014,7 +1014,7 @@ class BucketMetadataPatchBuilder {
   internal::PatchBuilder labels_subpatch_;
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/bucket_metadata_test.cc b/google/cloud/storage/bucket_metadata_test.cc
index 0309d92872d96..dcdadcf4db090 100644
--- a/google/cloud/storage/bucket_metadata_test.cc
+++ b/google/cloud/storage/bucket_metadata_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::HasSubstr;
@@ -1256,7 +1256,7 @@ TEST(BucketMetadataPatchBuilder, ResetWebsite) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/bucket_test.cc b/google/cloud/storage/bucket_test.cc
index 011818f972fbf..8dd8a39c0846a 100644
--- a/google/cloud/storage/bucket_test.cc
+++ b/google/cloud/storage/bucket_test.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::TransientError;
@@ -482,7 +482,7 @@ TEST_F(BucketTest, LockBucketRetentionPolicyPermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client.cc b/google/cloud/storage/client.cc
index 50c4bb321f9a0..8792a938d2512 100644
--- a/google/cloud/storage/client.cc
+++ b/google/cloud/storage/client.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 static_assert(std::is_copy_constructible<storage::Client>::value,
               "storage::Client must be constructible");
@@ -514,7 +514,7 @@ Status ScopedDeleter::ExecuteDelete() {
 
 }  // namespace internal
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client.h b/google/cloud/storage/client.h
index c75bb67b52077..905113b5b1db7 100644
--- a/google/cloud/storage/client.h
+++ b/google/cloud/storage/client.h
@@ -45,7 +45,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 class NonResumableParallelUploadState;
 class ResumableParallelUploadState;
@@ -3594,7 +3594,7 @@ StatusOr<ObjectMetadata> ComposeMany(
   return result;
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_bucket_acl_test.cc b/google/cloud/storage/client_bucket_acl_test.cc
index 269c1b4c305dc..b5ea6981d8939 100644
--- a/google/cloud/storage/client_bucket_acl_test.cc
+++ b/google/cloud/storage/client_bucket_acl_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::TransientError;
@@ -395,7 +395,7 @@ TEST_F(BucketAccessControlsTest, PatchBucketAclPermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_default_object_acl_test.cc b/google/cloud/storage/client_default_object_acl_test.cc
index 4fe25dd3c992c..8231d93aae0de 100644
--- a/google/cloud/storage/client_default_object_acl_test.cc
+++ b/google/cloud/storage/client_default_object_acl_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::TransientError;
@@ -356,7 +356,7 @@ TEST_F(DefaultObjectAccessControlsTest, PatchDefaultObjectAclPermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_notifications_test.cc b/google/cloud/storage/client_notifications_test.cc
index b378f11b0f947..ca66efa1665d6 100644
--- a/google/cloud/storage/client_notifications_test.cc
+++ b/google/cloud/storage/client_notifications_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::TransientError;
@@ -231,7 +231,7 @@ TEST_F(NotificationsTest, DeleteNotificationPermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_object_copy_test.cc b/google/cloud/storage/client_object_copy_test.cc
index 3a28d765b580a..eeb8368aa1da4 100644
--- a/google/cloud/storage/client_object_copy_test.cc
+++ b/google/cloud/storage/client_object_copy_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::TransientError;
@@ -295,7 +295,7 @@ TEST_F(ObjectCopyTest, RewriteObjectPermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_options.cc b/google/cloud/storage/client_options.cc
index dff04136a5190..935a83ef87ea6 100644
--- a/google/cloud/storage/client_options.cc
+++ b/google/cloud/storage/client_options.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::GetEnv;
 
@@ -294,7 +294,7 @@ ClientOptions& ClientOptions::SetUploadBufferSize(std::size_t size) {
   return *this;
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_options.h b/google/cloud/storage/client_options.h
index 39603425b1475..0526963cadbac 100644
--- a/google/cloud/storage/client_options.h
+++ b/google/cloud/storage/client_options.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class ClientOptions;
 namespace internal {
 std::string JsonEndpoint(Options const&);
@@ -275,7 +275,7 @@ class ClientOptions {
   std::string user_agent_prefix_;
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_options_test.cc b/google/cloud/storage/client_options_test.cc
index dc47749245af6..30f1242ad1c35 100644
--- a/google/cloud/storage/client_options_test.cc
+++ b/google/cloud/storage/client_options_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::testing_util::IsOk;
 using ::testing::IsEmpty;
@@ -340,7 +340,7 @@ TEST_F(ClientOptionsTest, DefaultOptions) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_service_account_test.cc b/google/cloud/storage/client_service_account_test.cc
index 756d9f0842e9a..83eb0be504b11 100644
--- a/google/cloud/storage/client_service_account_test.cc
+++ b/google/cloud/storage/client_service_account_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::TransientError;
@@ -242,7 +242,7 @@ TEST(DefaultCtorsWork, Trivial) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_sign_policy_document_test.cc b/google/cloud/storage/client_sign_policy_document_test.cc
index 13f60b4f2cc7b..7315d7d56e5a7 100644
--- a/google/cloud/storage/client_sign_policy_document_test.cc
+++ b/google/cloud/storage/client_sign_policy_document_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::TransientError;
@@ -276,7 +276,7 @@ TEST(CreateSignedPolicyDocTest, SignV4VirtualHostname) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_sign_url_test.cc b/google/cloud/storage/client_sign_url_test.cc
index 19d2fcf64b96a..c9be687b470c6 100644
--- a/google/cloud/storage/client_sign_url_test.cc
+++ b/google/cloud/storage/client_sign_url_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::TransientError;
@@ -269,7 +269,7 @@ TEST_F(CreateSignedUrlTest, V4SignPermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_test.cc b/google/cloud/storage/client_test.cc
index 653577961a334..41d1617c51fdd 100644
--- a/google/cloud/storage/client_test.cc
+++ b/google/cloud/storage/client_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::internal::ClientImplDetails;
@@ -186,7 +186,7 @@ TEST_F(ClientTest, DeprecatedButNotDecommissioned) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/client_write_object_test.cc b/google/cloud/storage/client_write_object_test.cc
index e919a232bb404..e543cea4b3f7c 100644
--- a/google/cloud/storage/client_write_object_test.cc
+++ b/google/cloud/storage/client_write_object_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::PermanentError;
@@ -375,7 +375,7 @@ TEST_F(WriteObjectTest, UploadFile) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/download_options.h b/google/cloud/storage/download_options.h
index 92a863af68dde..b2686c16b957d 100644
--- a/google/cloud/storage/download_options.h
+++ b/google/cloud/storage/download_options.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 struct ReadRangeData {
   std::int64_t begin;
   std::int64_t end;
@@ -70,7 +70,7 @@ struct ReadLast : public internal::ComplexOption<ReadLast, std::int64_t> {
   static char const* name() { return "read-last"; }
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/grpc_plugin.cc b/google/cloud/storage/grpc_plugin.cc
index 4001d7281ab88..d6d0a2d152a4d 100644
--- a/google/cloud/storage/grpc_plugin.cc
+++ b/google/cloud/storage/grpc_plugin.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage_experimental {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace {
 absl::optional<std::string> GrpcConfig() {
@@ -43,7 +43,7 @@ google::cloud::storage::Client DefaultGrpcClient(Options opts) {
       storage::internal::HybridClient::Create(opts));
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage_experimental
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/grpc_plugin.h b/google/cloud/storage/grpc_plugin.h
index 24e4229f1d6e1..7e8216841209b 100644
--- a/google/cloud/storage/grpc_plugin.h
+++ b/google/cloud/storage/grpc_plugin.h
@@ -28,7 +28,7 @@ namespace cloud {
  * change without notice, including removal.
  */
 namespace storage_experimental {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Low-level experimental settings for the GCS+gRPC plugin.
@@ -71,7 +71,7 @@ struct GrpcPluginOption {
  */
 google::cloud::storage::Client DefaultGrpcClient(Options opts = {});
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage_experimental
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/hash_mismatch_error.h b/google/cloud/storage/hash_mismatch_error.h
index b6b20682b22ba..4a947b5240b3a 100644
--- a/google/cloud/storage/hash_mismatch_error.h
+++ b/google/cloud/storage/hash_mismatch_error.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * Report checksum mismatches as exceptions.
@@ -42,7 +42,7 @@ class HashMismatchError : public std::ios_base::failure {
   std::string computed_hash_;
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/hashing_options.cc b/google/cloud/storage/hashing_options.cc
index 8e68daca01820..e858181b565b4 100644
--- a/google/cloud/storage/hashing_options.cc
+++ b/google/cloud/storage/hashing_options.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 std::string ComputeMD5Hash(std::string const& payload) {
   return internal::Base64Encode(internal::MD5Hash(payload));
@@ -33,7 +33,7 @@ std::string ComputeCrc32cChecksum(std::string const& payload) {
   return internal::Base64Encode(hash);
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/hashing_options.h b/google/cloud/storage/hashing_options.h
index 25427e49c63cd..301656f987a84 100644
--- a/google/cloud/storage/hashing_options.h
+++ b/google/cloud/storage/hashing_options.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Provide a pre-computed MD5 hash value.
  *
@@ -125,7 +125,7 @@ struct DisableCrc32cChecksum
   static char const* name() { return "disable-crc32c-checksum"; }
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/hashing_options_test.cc b/google/cloud/storage/hashing_options_test.cc
index e7e8f84f7d768..c2911a69efbe7 100644
--- a/google/cloud/storage/hashing_options_test.cc
+++ b/google/cloud/storage/hashing_options_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(ComputeMD5HashTest, Empty) {
@@ -54,7 +54,7 @@ TEST(ComputeCrc32cChecksumTest, Simple) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/hmac_key_metadata.cc b/google/cloud/storage/hmac_key_metadata.cc
index 69ce9879920ea..f0be0ce925031 100644
--- a/google/cloud/storage/hmac_key_metadata.cc
+++ b/google/cloud/storage/hmac_key_metadata.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::ostream& operator<<(std::ostream& os, HmacKeyMetadata const& rhs) {
   return os << "HmacKeyMetadata={id=" << rhs.id() << ", kind=" << rhs.kind()
             << ", access_id=" << rhs.access_id() << ", etag=" << rhs.etag()
@@ -30,7 +30,7 @@ std::ostream& operator<<(std::ostream& os, HmacKeyMetadata const& rhs) {
             << google::cloud::internal::FormatRfc3339(rhs.updated()) << "}";
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/hmac_key_metadata.h b/google/cloud/storage/hmac_key_metadata.h
index 66ca5e42b278e..bfa44ff26876f 100644
--- a/google/cloud/storage/hmac_key_metadata.h
+++ b/google/cloud/storage/hmac_key_metadata.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct HmacKeyMetadataParser;
 }  // namespace internal
@@ -112,7 +112,7 @@ inline bool operator!=(HmacKeyMetadata const& lhs, HmacKeyMetadata const& rhs) {
 
 std::ostream& operator<<(std::ostream& os, HmacKeyMetadata const& rhs);
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/hmac_key_metadata_test.cc b/google/cloud/storage/hmac_key_metadata_test.cc
index d4637e4e5f525..9d602dbff5322 100644
--- a/google/cloud/storage/hmac_key_metadata_test.cc
+++ b/google/cloud/storage/hmac_key_metadata_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::HasSubstr;
@@ -99,7 +99,7 @@ TEST(HmacKeyMetadataTest, SetETag) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/iam_policy.cc b/google/cloud/storage/iam_policy.cc
index 8882638d8b6cb..4e48e6fde8216 100644
--- a/google/cloud/storage/iam_policy.cc
+++ b/google/cloud/storage/iam_policy.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 template <typename Functor>
 Status IsOfTypeIfPresent(nlohmann::json const& json,
@@ -469,7 +469,7 @@ std::ostream& operator<<(std::ostream& os, NativeIamPolicy const& rhs) {
   return os << "}, etag=" << rhs.etag() << "}";
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/iam_policy.h b/google/cloud/storage/iam_policy.h
index 9fb1f501042f9..c1ae22d4fdea6 100644
--- a/google/cloud/storage/iam_policy.h
+++ b/google/cloud/storage/iam_policy.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Represents a google::type::Expr.
  *
@@ -167,7 +167,7 @@ class NativeIamPolicy {
 
 std::ostream& operator<<(std::ostream& os, NativeIamPolicy const& rhs);
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/idempotency_policy.cc b/google/cloud/storage/idempotency_policy.cc
index 37c6674f448c9..6ff6624099b1b 100644
--- a/google/cloud/storage/idempotency_policy.cc
+++ b/google/cloud/storage/idempotency_policy.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::unique_ptr<IdempotencyPolicy> AlwaysRetryIdempotencyPolicy::clone() const {
   return absl::make_unique<AlwaysRetryIdempotencyPolicy>(*this);
 }
@@ -531,7 +531,7 @@ bool StrictIdempotencyPolicy::IsIdempotent(
   return true;
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/idempotency_policy.h b/google/cloud/storage/idempotency_policy.h
index 349fa2bebeede..b508f14990489 100644
--- a/google/cloud/storage/idempotency_policy.h
+++ b/google/cloud/storage/idempotency_policy.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define the interface for the idempotency policy.
  *
@@ -456,7 +456,7 @@ class StrictIdempotencyPolicy : public IdempotencyPolicy {
   //@}
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/idempotency_policy_test.cc b/google/cloud/storage/idempotency_policy_test.cc
index 77d4329874c5f..43b2d0edc154b 100644
--- a/google/cloud/storage/idempotency_policy_test.cc
+++ b/google/cloud/storage/idempotency_policy_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(StrictIdempotencyPolicyTest, ListBuckets) {
@@ -639,7 +639,7 @@ TEST(StrictIdempotencyPolicyTest, UploadChunk) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/access_control_common.h b/google/cloud/storage/internal/access_control_common.h
index f55cd9abfa863..366f4c96eaae6 100644
--- a/google/cloud/storage/internal/access_control_common.h
+++ b/google/cloud/storage/internal/access_control_common.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct AccessControlCommonParser;
 }  // namespace internal
@@ -167,7 +167,7 @@ inline bool operator!=(AccessControlCommon const& lhs,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/access_control_common_parser.cc b/google/cloud/storage/internal/access_control_common_parser.cc
index 227ec95b1f274..aacfba95efba9 100644
--- a/google/cloud/storage/internal/access_control_common_parser.cc
+++ b/google/cloud/storage/internal/access_control_common_parser.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 Status AccessControlCommonParser::FromJson(AccessControlCommon& result,
                                            nlohmann::json const& json) {
@@ -45,7 +45,7 @@ Status AccessControlCommonParser::FromJson(AccessControlCommon& result,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/access_control_common_parser.h b/google/cloud/storage/internal/access_control_common_parser.h
index 4db795a2d3ccc..9f17816401a6a 100644
--- a/google/cloud/storage/internal/access_control_common_parser.h
+++ b/google/cloud/storage/internal/access_control_common_parser.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct AccessControlCommonParser {
   static Status FromJson(AccessControlCommon& result,
@@ -30,7 +30,7 @@ struct AccessControlCommonParser {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/access_control_common_parser_test.cc b/google/cloud/storage/internal/access_control_common_parser_test.cc
index 17dac47c37c19..78629ce2d5d31 100644
--- a/google/cloud/storage/internal/access_control_common_parser_test.cc
+++ b/google/cloud/storage/internal/access_control_common_parser_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::Eq;
@@ -40,7 +40,7 @@ TEST(AccessControlCommonParserTest, FromJson) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/access_control_common_test.cc b/google/cloud/storage/internal/access_control_common_test.cc
index 812810570f71f..a9f46f288e364 100644
--- a/google/cloud/storage/internal/access_control_common_test.cc
+++ b/google/cloud/storage/internal/access_control_common_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 /// @test Verify the well-known values defined in AccessControlCommon.
@@ -33,7 +33,7 @@ TEST(ccessControlCommonTest, WellKnownValues) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/access_token_credentials.cc b/google/cloud/storage/internal/access_token_credentials.cc
index 6c3ff17054427..bd772432104d1 100644
--- a/google/cloud/storage/internal/access_token_credentials.cc
+++ b/google/cloud/storage/internal/access_token_credentials.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 AccessTokenCredentials::AccessTokenCredentials(
@@ -29,7 +29,7 @@ StatusOr<std::string> AccessTokenCredentials::AuthorizationHeader() {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/access_token_credentials.h b/google/cloud/storage/internal/access_token_credentials.h
index 3d24a81fb188c..d60517f95040b 100644
--- a/google/cloud/storage/internal/access_token_credentials.h
+++ b/google/cloud/storage/internal/access_token_credentials.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 class AccessTokenCredentials : public oauth2::Credentials {
@@ -38,7 +38,7 @@ class AccessTokenCredentials : public oauth2::Credentials {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/access_token_credentials_test.cc b/google/cloud/storage/internal/access_token_credentials_test.cc
index 41c927e896f8e..3dc75e5967530 100644
--- a/google/cloud/storage/internal/access_token_credentials_test.cc
+++ b/google/cloud/storage/internal/access_token_credentials_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -38,7 +38,7 @@ TEST(AccessTokenCredentials, Simple) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/binary_data_as_debug_string.cc b/google/cloud/storage/internal/binary_data_as_debug_string.cc
index 4c9b63c5c3e96..29f780235cdd6 100644
--- a/google/cloud/storage/internal/binary_data_as_debug_string.cc
+++ b/google/cloud/storage/internal/binary_data_as_debug_string.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 std::string BinaryDataAsDebugString(char const* data, std::size_t size,
                                     std::size_t max_output_bytes) {
@@ -81,7 +81,7 @@ std::string BinaryDataAsDebugString(char const* data, std::size_t size,
   return result;
 }
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/binary_data_as_debug_string.h b/google/cloud/storage/internal/binary_data_as_debug_string.h
index 8117a42dd8a3d..49952a1dc33ab 100644
--- a/google/cloud/storage/internal/binary_data_as_debug_string.h
+++ b/google/cloud/storage/internal/binary_data_as_debug_string.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Formats a block of data for debug printing.
@@ -35,7 +35,7 @@ namespace internal {
 std::string BinaryDataAsDebugString(char const* data, std::size_t size,
                                     std::size_t max_output_bytes = 0);
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/binary_data_as_debug_string_test.cc b/google/cloud/storage/internal/binary_data_as_debug_string_test.cc
index b62a52955ca0b..34d1f0513f03c 100644
--- a/google/cloud/storage/internal/binary_data_as_debug_string_test.cc
+++ b/google/cloud/storage/internal/binary_data_as_debug_string_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -68,7 +68,7 @@ TEST(BinaryDataAsDebugStringTest, Limit) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_access_control_parser.cc b/google/cloud/storage/internal/bucket_access_control_parser.cc
index c8e26caf5af8f..59ad957acd644 100644
--- a/google/cloud/storage/internal/bucket_access_control_parser.cc
+++ b/google/cloud/storage/internal/bucket_access_control_parser.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<BucketAccessControl> BucketAccessControlParser::FromJson(
     nlohmann::json const& json) {
@@ -41,7 +41,7 @@ StatusOr<BucketAccessControl> BucketAccessControlParser::FromString(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_access_control_parser.h b/google/cloud/storage/internal/bucket_access_control_parser.h
index af1df78813ff4..f5fc03495d12f 100644
--- a/google/cloud/storage/internal/bucket_access_control_parser.h
+++ b/google/cloud/storage/internal/bucket_access_control_parser.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct BucketAccessControlParser {
   static StatusOr<BucketAccessControl> FromJson(nlohmann::json const& json);
@@ -31,7 +31,7 @@ struct BucketAccessControlParser {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_acl_requests.cc b/google/cloud/storage/internal/bucket_acl_requests.cc
index fdb244551ad2e..bf23c43350a0a 100644
--- a/google/cloud/storage/internal/bucket_acl_requests.cc
+++ b/google/cloud/storage/internal/bucket_acl_requests.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 std::ostream& operator<<(std::ostream& os, ListBucketAclRequest const& r) {
   os << "ListBucketAclRequest={bucket_name=" << r.bucket_name();
@@ -104,7 +104,7 @@ std::ostream& operator<<(std::ostream& os, PatchBucketAclRequest const& r) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_acl_requests.h b/google/cloud/storage/internal/bucket_acl_requests.h
index 5a49f6f54b037..3b2a3e64a4687 100644
--- a/google/cloud/storage/internal/bucket_acl_requests.h
+++ b/google/cloud/storage/internal/bucket_acl_requests.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// Represents a request to call the `BucketAccessControl: list` API.
 class ListBucketAclRequest
@@ -165,7 +165,7 @@ class PatchBucketAclRequest
 std::ostream& operator<<(std::ostream& os, PatchBucketAclRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_acl_requests_test.cc b/google/cloud/storage/internal/bucket_acl_requests_test.cc
index 9335ef5c28c99..cc336090e0a44 100644
--- a/google/cloud/storage/internal/bucket_acl_requests_test.cc
+++ b/google/cloud/storage/internal/bucket_acl_requests_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -206,7 +206,7 @@ TEST(PatchObjectAclRequestTest, PatchStream) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_metadata_parser.cc b/google/cloud/storage/internal/bucket_metadata_parser.cc
index c47c60c16481e..b007305186c98 100644
--- a/google/cloud/storage/internal/bucket_metadata_parser.cc
+++ b/google/cloud/storage/internal/bucket_metadata_parser.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 void SetIfNotEmpty(nlohmann::json& json, char const* key,
@@ -515,7 +515,7 @@ std::string BucketMetadataToJsonString(BucketMetadata const& meta) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_metadata_parser.h b/google/cloud/storage/internal/bucket_metadata_parser.h
index 544dc0240fb3c..d3d486991343a 100644
--- a/google/cloud/storage/internal/bucket_metadata_parser.h
+++ b/google/cloud/storage/internal/bucket_metadata_parser.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct BucketMetadataParser {
   static StatusOr<BucketMetadata> FromJson(nlohmann::json const& json);
@@ -33,7 +33,7 @@ struct BucketMetadataParser {
 std::string BucketMetadataToJsonString(BucketMetadata const& meta);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_requests.cc b/google/cloud/storage/internal/bucket_requests.cc
index 4ebd477a7ddb9..e890dfcf62b68 100644
--- a/google/cloud/storage/internal/bucket_requests.cc
+++ b/google/cloud/storage/internal/bucket_requests.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -450,7 +450,7 @@ std::ostream& operator<<(std::ostream& os,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_requests.h b/google/cloud/storage/internal/bucket_requests.h
index 7d0d56f212f9e..5fecb9ab8d8e7 100644
--- a/google/cloud/storage/internal/bucket_requests.h
+++ b/google/cloud/storage/internal/bucket_requests.h
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Requests the list of buckets for a project.
@@ -305,7 +305,7 @@ std::ostream& operator<<(std::ostream& os,
                          LockBucketRetentionPolicyRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/bucket_requests_test.cc b/google/cloud/storage/internal/bucket_requests_test.cc
index cd728583da272..1786953be64cd 100644
--- a/google/cloud/storage/internal/bucket_requests_test.cc
+++ b/google/cloud/storage/internal/bucket_requests_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -1018,7 +1018,7 @@ TEST(BucketRequestsTest, LockBucketRetentionPolicyRequest) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/common_metadata.h b/google/cloud/storage/internal/common_metadata.h
index feba918038177..93a440eb25a8c 100644
--- a/google/cloud/storage/internal/common_metadata.h
+++ b/google/cloud/storage/internal/common_metadata.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// A simple wrapper for the `owner` field in `internal::CommonMetadata`.
 struct Owner {
   std::string entity;
@@ -142,7 +142,7 @@ inline bool operator!=(CommonMetadata<T> const& lhs,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/common_metadata_parser.h b/google/cloud/storage/internal/common_metadata_parser.h
index 3b1625cdedf99..7cc34edc3bbab 100644
--- a/google/cloud/storage/internal/common_metadata_parser.h
+++ b/google/cloud/storage/internal/common_metadata_parser.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 template <typename Derived>
 struct CommonMetadataParser {
@@ -63,7 +63,7 @@ struct CommonMetadataParser {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/complex_option.h b/google/cloud/storage/internal/complex_option.h
index 7bbe3c4475fbf..349ab213604c2 100644
--- a/google/cloud/storage/internal/complex_option.h
+++ b/google/cloud/storage/internal/complex_option.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * A complex option is a request optional parameter that is neither a header
@@ -66,7 +66,7 @@ std::ostream& operator<<(std::ostream& os,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/complex_option_test.cc b/google/cloud/storage/internal/complex_option_test.cc
index b6918ad12bd28..f0826e0103125 100644
--- a/google/cloud/storage/internal/complex_option_test.cc
+++ b/google/cloud/storage/internal/complex_option_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -40,7 +40,7 @@ TEST(ComplexOptionTest, ValueOrNonEmptyCase) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/compute_engine_util.cc b/google/cloud/storage/internal/compute_engine_util.cc
index c48dd92238c9c..46f7af88d11bb 100644
--- a/google/cloud/storage/internal/compute_engine_util.cc
+++ b/google/cloud/storage/internal/compute_engine_util.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::string GceMetadataHostname() {
@@ -28,7 +28,7 @@ std::string GceMetadataHostname() {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/compute_engine_util.h b/google/cloud/storage/internal/compute_engine_util.h
index b1d4a9f9ba764..c4f367f9c99b6 100644
--- a/google/cloud/storage/internal/compute_engine_util.h
+++ b/google/cloud/storage/internal/compute_engine_util.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -50,7 +50,7 @@ inline char const* GceMetadataHostnameEnvVar() {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/compute_engine_util_test.cc b/google/cloud/storage/internal/compute_engine_util_test.cc
index 8573b771acf5c..ff16621353567 100644
--- a/google/cloud/storage/internal/compute_engine_util_test.cc
+++ b/google/cloud/storage/internal/compute_engine_util_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -46,7 +46,7 @@ TEST_F(ComputeEngineUtilTest, CanOverrideGceMetadataHostname) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/const_buffer.cc b/google/cloud/storage/internal/const_buffer.cc
index 0c9cd47160276..daf6c44cd74db 100644
--- a/google/cloud/storage/internal/const_buffer.cc
+++ b/google/cloud/storage/internal/const_buffer.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 void PopFrontBytes(ConstBufferSequence& s, std::size_t count) {
@@ -40,7 +40,7 @@ void PopFrontBytes(ConstBufferSequence& s, std::size_t count) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/const_buffer.h b/google/cloud/storage/internal/const_buffer.h
index d362b9ac9d8af..7c66d2d4f2fb1 100644
--- a/google/cloud/storage/internal/const_buffer.h
+++ b/google/cloud/storage/internal/const_buffer.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /// Represent a memory range. Use to upload with low copying
@@ -43,7 +43,7 @@ inline std::size_t TotalBytes(ConstBufferSequence const& s) {
 void PopFrontBytes(ConstBufferSequence& s, std::size_t count);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/const_buffer_test.cc b/google/cloud/storage/internal/const_buffer_test.cc
index 205760760b567..16ef9115259b0 100644
--- a/google/cloud/storage/internal/const_buffer_test.cc
+++ b/google/cloud/storage/internal/const_buffer_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -80,7 +80,7 @@ TEST(ConstBufferTest, PopFrontPartial) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_client.cc b/google/cloud/storage/internal/curl_client.cc
index 9bb965198718e..e809c384ca2d2 100644
--- a/google/cloud/storage/internal/curl_client.cc
+++ b/google/cloud/storage/internal/curl_client.cc
@@ -35,7 +35,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -1425,7 +1425,7 @@ StatusOr<ObjectMetadata> CurlClient::InsertObjectMediaSimple(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_client.h b/google/cloud/storage/internal/curl_client.h
index 2e43eb02b67fa..73af59e9d013f 100644
--- a/google/cloud/storage/internal/curl_client.h
+++ b/google/cloud/storage/internal/curl_client.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 class CurlRequestBuilder;
 
@@ -244,7 +244,7 @@ class CurlClient : public RawClient,
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_client_test.cc b/google/cloud/storage/internal/curl_client_test.cc
index be692c4f55ab2..f44832179f2bd 100644
--- a/google/cloud/storage/internal/curl_client_test.cc
+++ b/google/cloud/storage/internal/curl_client_test.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -560,7 +560,7 @@ INSTANTIATE_TEST_SUITE_P(LibCurlFailure, CurlClientTest,
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_download_request.cc b/google/cloud/storage/internal/curl_download_request.cc
index 807ec2fee58e6..705edbc537b1c 100644
--- a/google/cloud/storage/internal/curl_download_request.cc
+++ b/google/cloud/storage/internal/curl_download_request.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::string ExtractHashValue(std::string const& hash_header,
@@ -482,7 +482,7 @@ Status CurlDownloadRequest::AsStatus(CURLMcode result, char const* where) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_download_request.h b/google/cloud/storage/internal/curl_download_request.h
index 9bba481b208ea..e42075bcbe45d 100644
--- a/google/cloud/storage/internal/curl_download_request.h
+++ b/google/cloud/storage/internal/curl_download_request.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// Parse the `x-goog-hash` header and get one of the hashes.
 std::string ExtractHashValue(std::string const& hash_header,
@@ -176,7 +176,7 @@ class CurlDownloadRequest : public ObjectReadSource {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_download_request_test.cc b/google/cloud/storage/internal/curl_download_request_test.cc
index fa1a7106de22f..588235b9435a8 100644
--- a/google/cloud/storage/internal/curl_download_request_test.cc
+++ b/google/cloud/storage/internal/curl_download_request_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -86,7 +86,7 @@ TEST(CurlDownloadRequest, MakeReadResult) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_handle.cc b/google/cloud/storage/internal/curl_handle.cc
index 32b636b0bcff6..d09946acd0b88 100644
--- a/google/cloud/storage/internal/curl_handle.cc
+++ b/google/cloud/storage/internal/curl_handle.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -374,7 +374,7 @@ Status CurlHandle::AsStatus(CURLcode e, char const* where) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_handle.h b/google/cloud/storage/internal/curl_handle.h
index 090a6f305db7b..f37494576610a 100644
--- a/google/cloud/storage/internal/curl_handle.h
+++ b/google/cloud/storage/internal/curl_handle.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 void AssertOptionSuccessImpl(
     CURLcode e, CURLoption opt, char const* where,
@@ -176,7 +176,7 @@ class CurlHandle {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_handle_factory.cc b/google/cloud/storage/internal/curl_handle_factory.cc
index 69e5f763cb71d..a6d1b738c865c 100644
--- a/google/cloud/storage/internal/curl_handle_factory.cc
+++ b/google/cloud/storage/internal/curl_handle_factory.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 void CurlHandleFactory::SetCurlStringOption(CURL* handle, CURLoption option_tag,
@@ -159,7 +159,7 @@ void PooledCurlHandleFactory::SetCurlOptions(CURL* handle) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_handle_factory.h b/google/cloud/storage/internal/curl_handle_factory.h
index 8dbb54d01df3c..b576b64cb1db8 100644
--- a/google/cloud/storage/internal/curl_handle_factory.h
+++ b/google/cloud/storage/internal/curl_handle_factory.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Implements the Factory Pattern for CURL handles (and multi-handles).
@@ -148,7 +148,7 @@ class PooledCurlHandleFactory : public CurlHandleFactory {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_handle_factory_test.cc b/google/cloud/storage/internal/curl_handle_factory_test.cc
index ba5d6323009c9..bc8c7890601eb 100644
--- a/google/cloud/storage/internal/curl_handle_factory_test.cc
+++ b/google/cloud/storage/internal/curl_handle_factory_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -111,7 +111,7 @@ TEST(CurlHandleFactoryTest, PooledFactoryChannelOptionsCallsSetOptions) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_handle_test.cc b/google/cloud/storage/internal/curl_handle_test.cc
index 414d74a947694..b7570f9b25703 100644
--- a/google/cloud/storage/internal/curl_handle_test.cc
+++ b/google/cloud/storage/internal/curl_handle_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -95,7 +95,7 @@ TEST(AssertOptionSuccess, FunctionPtrWithError) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_request.cc b/google/cloud/storage/internal/curl_request.cc
index 9aa0c181ee749..fcb58136a7040 100644
--- a/google/cloud/storage/internal/curl_request.cc
+++ b/google/cloud/storage/internal/curl_request.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 extern "C" size_t CurlRequestOnWriteData(char* ptr, size_t size, size_t nmemb,
@@ -153,7 +153,7 @@ std::size_t CurlRequest::OnHeaderData(char* contents, std::size_t size,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_request.h b/google/cloud/storage/internal/curl_request.h
index 8f368b6227f77..557b77666d7ea 100644
--- a/google/cloud/storage/internal/curl_request.h
+++ b/google/cloud/storage/internal/curl_request.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 extern "C" size_t CurlRequestOnWriteData(char* ptr, size_t size, size_t nmemb,
                                          void* userdata);
@@ -82,7 +82,7 @@ class CurlRequest {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_request_builder.cc b/google/cloud/storage/internal/curl_request_builder.cc
index 72c68da962b68..98505d39310e4 100644
--- a/google/cloud/storage/internal/curl_request_builder.cc
+++ b/google/cloud/storage/internal/curl_request_builder.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 char const* InitialQueryParameterSeparator(std::string const& url) {
@@ -145,7 +145,7 @@ void CurlRequestBuilder::ValidateBuilderState(char const* where) const {
   }
 }
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_request_builder.h b/google/cloud/storage/internal/curl_request_builder.h
index 3ba668e4c8732..9062d7a1243e3 100644
--- a/google/cloud/storage/internal/curl_request_builder.h
+++ b/google/cloud/storage/internal/curl_request_builder.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Implements the Builder pattern for CurlRequest, and CurlUploadRequest.
@@ -200,7 +200,7 @@ class CurlRequestBuilder {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_resumable_upload_session.cc b/google/cloud/storage/internal/curl_resumable_upload_session.cc
index 29308bd77c281..1513c6a383ac7 100644
--- a/google/cloud/storage/internal/curl_resumable_upload_session.cc
+++ b/google/cloud/storage/internal/curl_resumable_upload_session.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 StatusOr<ResumableUploadResponse> CurlResumableUploadSession::UploadChunk(
@@ -85,7 +85,7 @@ void CurlResumableUploadSession::Update(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_resumable_upload_session.h b/google/cloud/storage/internal/curl_resumable_upload_session.h
index 8437aab00c4ed..e228adcf4b661 100644
--- a/google/cloud/storage/internal/curl_resumable_upload_session.h
+++ b/google/cloud/storage/internal/curl_resumable_upload_session.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Implement a ResumableUploadSession that delegates to a CurlClient.
@@ -69,7 +69,7 @@ class CurlResumableUploadSession : public ResumableUploadSession {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_resumable_upload_session_test.cc b/google/cloud/storage/internal/curl_resumable_upload_session_test.cc
index b6a6aa6997beb..843404e7b57de 100644
--- a/google/cloud/storage/internal/curl_resumable_upload_session_test.cc
+++ b/google/cloud/storage/internal/curl_resumable_upload_session_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -226,7 +226,7 @@ TEST(CurlResumableUploadSessionTest, Empty) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_wrappers.cc b/google/cloud/storage/internal/curl_wrappers.cc
index 2a31452148c78..5a38df5f4f25a 100644
--- a/google/cloud/storage/internal/curl_wrappers.cc
+++ b/google/cloud/storage/internal/curl_wrappers.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -265,7 +265,7 @@ void CurlInitializeOnce(Options const& options) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_wrappers.h b/google/cloud/storage/internal/curl_wrappers.h
index 44b2ff775cf1d..337b969e75335 100644
--- a/google/cloud/storage/internal/curl_wrappers.h
+++ b/google/cloud/storage/internal/curl_wrappers.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 #ifndef CURL_AT_LEAST_VERSION
@@ -69,7 +69,7 @@ bool SslLibraryNeedsLocking(std::string const& curl_ssl_id);
 long VersionToCurlCode(std::string const& v);  // NOLINT(google-runtime-int)
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_wrappers_disable_sigpipe_handler_test.cc b/google/cloud/storage/internal/curl_wrappers_disable_sigpipe_handler_test.cc
index 56deff464e64e..eddb2c22d51d3 100644
--- a/google/cloud/storage/internal/curl_wrappers_disable_sigpipe_handler_test.cc
+++ b/google/cloud/storage/internal/curl_wrappers_disable_sigpipe_handler_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -52,7 +52,7 @@ TEST(CurlWrappers, SigpipeHandlerDisabledTest) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_wrappers_enable_sigpipe_handler_test.cc b/google/cloud/storage/internal/curl_wrappers_enable_sigpipe_handler_test.cc
index a6dd40b273e5d..efead66f9536c 100644
--- a/google/cloud/storage/internal/curl_wrappers_enable_sigpipe_handler_test.cc
+++ b/google/cloud/storage/internal/curl_wrappers_enable_sigpipe_handler_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -46,7 +46,7 @@ TEST(CurlWrappers, SigpipeHandlerEnabledTest) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_wrappers_locking_already_present_test.cc b/google/cloud/storage/internal/curl_wrappers_locking_already_present_test.cc
index 7f2d81ef29dee..dce71b28c42df 100644
--- a/google/cloud/storage/internal/curl_wrappers_locking_already_present_test.cc
+++ b/google/cloud/storage/internal/curl_wrappers_locking_already_present_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 // An empty callback just to test things.
@@ -39,7 +39,7 @@ TEST(CurlWrappers, LockingDisabledTest) {
 }
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_wrappers_locking_disabled_test.cc b/google/cloud/storage/internal/curl_wrappers_locking_disabled_test.cc
index 0156c169ec18c..42890c387f57e 100644
--- a/google/cloud/storage/internal/curl_wrappers_locking_disabled_test.cc
+++ b/google/cloud/storage/internal/curl_wrappers_locking_disabled_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 /// @test Verify that installing the libraries
@@ -31,7 +31,7 @@ TEST(CurlWrappers, LockingDisabledTest) {
 }
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_wrappers_locking_enabled_test.cc b/google/cloud/storage/internal/curl_wrappers_locking_enabled_test.cc
index 5a26755d43ef9..92167c3b29131 100644
--- a/google/cloud/storage/internal/curl_wrappers_locking_enabled_test.cc
+++ b/google/cloud/storage/internal/curl_wrappers_locking_enabled_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 /// @test Verify that installing the libraries
@@ -31,7 +31,7 @@ TEST(CurlWrappers, LockingEnabledTest) {
 }
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/curl_wrappers_test.cc b/google/cloud/storage/internal/curl_wrappers_test.cc
index 5a51ac8e7d702..85adf24b10a6e 100644
--- a/google/cloud/storage/internal/curl_wrappers_test.cc
+++ b/google/cloud/storage/internal/curl_wrappers_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -49,7 +49,7 @@ TEST(CurlWrappers, VersionToCurlCode) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/default_object_acl_requests.cc b/google/cloud/storage/internal/default_object_acl_requests.cc
index 54517d0113f28..4e641c3a277d6 100644
--- a/google/cloud/storage/internal/default_object_acl_requests.cc
+++ b/google/cloud/storage/internal/default_object_acl_requests.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 std::ostream& operator<<(std::ostream& os,
                          ListDefaultObjectAclRequest const& r) {
@@ -113,7 +113,7 @@ std::ostream& operator<<(std::ostream& os,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/default_object_acl_requests.h b/google/cloud/storage/internal/default_object_acl_requests.h
index 2fc65d6cc08df..89ebb819da71e 100644
--- a/google/cloud/storage/internal/default_object_acl_requests.h
+++ b/google/cloud/storage/internal/default_object_acl_requests.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /// Represents a request to call the `DefaultObjectAccessControls: list` API.
@@ -182,7 +182,7 @@ std::ostream& operator<<(std::ostream& os,
                          PatchDefaultObjectAclRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/default_object_acl_requests_test.cc b/google/cloud/storage/internal/default_object_acl_requests_test.cc
index 412ae43703135..94b4ab115369f 100644
--- a/google/cloud/storage/internal/default_object_acl_requests_test.cc
+++ b/google/cloud/storage/internal/default_object_acl_requests_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -212,7 +212,7 @@ TEST(DefaultObjectAclRequestTest, PatchStream) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/empty_response.cc b/google/cloud/storage/internal/empty_response.cc
index 869a29e6cce3a..d9ee1f76564ab 100644
--- a/google/cloud/storage/internal/empty_response.cc
+++ b/google/cloud/storage/internal/empty_response.cc
@@ -18,14 +18,14 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 std::ostream& operator<<(std::ostream& os, EmptyResponse const&) {
   return os << "EmptyResponse={}";
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/empty_response.h b/google/cloud/storage/internal/empty_response.h
index 62072891ae5fc..6a73d62c6f587 100644
--- a/google/cloud/storage/internal/empty_response.h
+++ b/google/cloud/storage/internal/empty_response.h
@@ -20,14 +20,14 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// A empty struct to represent empty responses.
 struct EmptyResponse {};
 
 std::ostream& operator<<(std::ostream& os, EmptyResponse const& r);
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/error_credentials.cc b/google/cloud/storage/internal/error_credentials.cc
index f1bbb426bdd7b..725ea1a29aa0b 100644
--- a/google/cloud/storage/internal/error_credentials.cc
+++ b/google/cloud/storage/internal/error_credentials.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 StatusOr<std::string> ErrorCredentials::AuthorizationHeader() {
@@ -25,7 +25,7 @@ StatusOr<std::string> ErrorCredentials::AuthorizationHeader() {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/error_credentials.h b/google/cloud/storage/internal/error_credentials.h
index c8e701c27c474..e2b120ec5dfed 100644
--- a/google/cloud/storage/internal/error_credentials.h
+++ b/google/cloud/storage/internal/error_credentials.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -56,7 +56,7 @@ class ErrorCredentials : public oauth2::Credentials {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/generate_message_boundary.h b/google/cloud/storage/internal/generate_message_boundary.h
index 61d26b6f34111..035cd3bd5f727 100644
--- a/google/cloud/storage/internal/generate_message_boundary.h
+++ b/google/cloud/storage/internal/generate_message_boundary.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -66,7 +66,7 @@ std::string GenerateMessageBoundary(
   return candidate;
 }
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/generate_message_boundary_test.cc b/google/cloud/storage/internal/generate_message_boundary_test.cc
index c4fde935ddcca..4aef044d28390 100644
--- a/google/cloud/storage/internal/generate_message_boundary_test.cc
+++ b/google/cloud/storage/internal/generate_message_boundary_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -83,7 +83,7 @@ TEST(GenerateMessageBoundaryTest, RequiresGrowth) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/generic_object_request.h b/google/cloud/storage/internal/generic_object_request.h
index d030b4fecb1a7..e33ca3a1990ac 100644
--- a/google/cloud/storage/internal/generic_object_request.h
+++ b/google/cloud/storage/internal/generic_object_request.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /// Common attributes for requests about objects.
@@ -54,7 +54,7 @@ class GenericObjectRequest : public GenericRequest<Derived, Parameters...> {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/generic_request.h b/google/cloud/storage/internal/generic_request.h
index 2d1ec85f1eb2d..8b836d56d6c5d 100644
--- a/google/cloud/storage/internal/generic_request.h
+++ b/google/cloud/storage/internal/generic_request.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Sets the user IP on an operation for quota enforcement purposes.
  *
@@ -226,7 +226,7 @@ class GenericRequest
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/generic_request_test.cc b/google/cloud/storage/internal/generic_request_test.cc
index 7c5a4814202ef..845454ebc5d02 100644
--- a/google/cloud/storage/internal/generic_request_test.cc
+++ b/google/cloud/storage/internal/generic_request_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -56,7 +56,7 @@ TEST(GenericRequestTest, SetOptionLValueLastBase) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_client.cc b/google/cloud/storage/internal/grpc_client.cc
index 9e0b656a15a47..a1bf34c830ca0 100644
--- a/google/cloud/storage/internal/grpc_client.cc
+++ b/google/cloud/storage/internal/grpc_client.cc
@@ -40,7 +40,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 using ::google::cloud::internal::GrpcAuthenticationStrategy;
@@ -1033,7 +1033,7 @@ std::string GrpcClient::ComputeMD5Hash(std::string const& payload) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_client.h b/google/cloud/storage/internal/grpc_client.h
index 1eb44051380b3..836a5d061a583 100644
--- a/google/cloud/storage/internal/grpc_client.h
+++ b/google/cloud/storage/internal/grpc_client.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -229,7 +229,7 @@ class GrpcClient : public RawClient,
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_client_failures_test.cc b/google/cloud/storage/internal/grpc_client_failures_test.cc
index 5cca7e8a13e2c..6fb8a72c0653f 100644
--- a/google/cloud/storage/internal/grpc_client_failures_test.cc
+++ b/google/cloud/storage/internal/grpc_client_failures_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -429,7 +429,7 @@ INSTANTIATE_TEST_SUITE_P(GrpcClientFailures, GrpcClientFailuresTest,
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_client_insert_object_media_test.cc b/google/cloud/storage/internal/grpc_client_insert_object_media_test.cc
index f98cf001cf456..0ed3d4a149941 100644
--- a/google/cloud/storage/internal/grpc_client_insert_object_media_test.cc
+++ b/google/cloud/storage/internal/grpc_client_insert_object_media_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -89,7 +89,7 @@ TEST(GrpcClientInsertObjectMediaTest, Small) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_client_object_request_test.cc b/google/cloud/storage/internal/grpc_client_object_request_test.cc
index da718a567ff30..7ed3cd5de089d 100644
--- a/google/cloud/storage/internal/grpc_client_object_request_test.cc
+++ b/google/cloud/storage/internal/grpc_client_object_request_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -528,7 +528,7 @@ TEST(GrpcClientObjectRequest, ReadObjectRangeRequestReadLastZero) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_client_read_object_test.cc b/google/cloud/storage/internal/grpc_client_read_object_test.cc
index a4c2b579760db..aae6b9e859b64 100644
--- a/google/cloud/storage/internal/grpc_client_read_object_test.cc
+++ b/google/cloud/storage/internal/grpc_client_read_object_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -97,7 +97,7 @@ TEST(GrpcClientReadObjectTest, WithExplicitTimeout) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_client_test.cc b/google/cloud/storage/internal/grpc_client_test.cc
index 2e71b92baf546..65d5f9bddce14 100644
--- a/google/cloud/storage/internal/grpc_client_test.cc
+++ b/google/cloud/storage/internal/grpc_client_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -324,7 +324,7 @@ TEST(GrpcClientToProto, ObjectAccessControlMinimalFields) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_configure_client_context.h b/google/cloud/storage/internal/grpc_configure_client_context.h
index 03a668e20e0c4..bcd0f57ed9505 100644
--- a/google/cloud/storage/internal/grpc_configure_client_context.h
+++ b/google/cloud/storage/internal/grpc_configure_client_context.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -60,7 +60,7 @@ void ApplyQueryParameters(grpc::ClientContext& context, Request const& request,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_configure_client_context_test.cc b/google/cloud/storage/internal/grpc_configure_client_context_test.cc
index ab4addfae8ca1..1c57ee28a10d3 100644
--- a/google/cloud/storage/internal/grpc_configure_client_context_test.cc
+++ b/google/cloud/storage/internal/grpc_configure_client_context_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -92,7 +92,7 @@ TEST(GrpcConfigureClientContext, ApplyQueryParametersQuotaUserAndUserIp) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_object_read_source.cc b/google/cloud/storage/internal/grpc_object_read_source.cc
index 79848fbb77245..9be0280b95b6a 100644
--- a/google/cloud/storage/internal/grpc_object_read_source.cc
+++ b/google/cloud/storage/internal/grpc_object_read_source.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 using HeadersMap = std::multimap<std::string, std::string>;
@@ -109,7 +109,7 @@ StatusOr<ReadSourceResult> GrpcObjectReadSource::Read(char* buf,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_object_read_source.h b/google/cloud/storage/internal/grpc_object_read_source.h
index b2fa50de8fc5f..15a95cd2776e3 100644
--- a/google/cloud/storage/internal/grpc_object_read_source.h
+++ b/google/cloud/storage/internal/grpc_object_read_source.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -70,7 +70,7 @@ class GrpcObjectReadSource : public ObjectReadSource {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_object_read_source_test.cc b/google/cloud/storage/internal/grpc_object_read_source_test.cc
index a48eb98f80f29..989ea0e09fb3e 100644
--- a/google/cloud/storage/internal/grpc_object_read_source_test.cc
+++ b/google/cloud/storage/internal/grpc_object_read_source_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -345,7 +345,7 @@ TEST(GrpcObjectReadSource, HandleExtraRead) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_resumable_upload_session.cc b/google/cloud/storage/internal/grpc_resumable_upload_session.cc
index 138851ff45b0d..f075ab31f50e0 100644
--- a/google/cloud/storage/internal/grpc_resumable_upload_session.cc
+++ b/google/cloud/storage/internal/grpc_resumable_upload_session.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 static_assert(
@@ -164,7 +164,7 @@ StatusOr<ResumableUploadResponse> GrpcResumableUploadSession::UploadGeneric(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_resumable_upload_session.h b/google/cloud/storage/internal/grpc_resumable_upload_session.h
index 21bfd68e40264..8c5f3f0863a1a 100644
--- a/google/cloud/storage/internal/grpc_resumable_upload_session.h
+++ b/google/cloud/storage/internal/grpc_resumable_upload_session.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// Implements the ResumableUploadSession interface for a gRPC client.
 class GrpcResumableUploadSession : public ResumableUploadSession {
@@ -70,7 +70,7 @@ class GrpcResumableUploadSession : public ResumableUploadSession {
   StatusOr<ResumableUploadResponse> last_response_;
 };
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_resumable_upload_session_test.cc b/google/cloud/storage/internal/grpc_resumable_upload_session_test.cc
index e10211d907990..f69c7d1d17d22 100644
--- a/google/cloud/storage/internal/grpc_resumable_upload_session_test.cc
+++ b/google/cloud/storage/internal/grpc_resumable_upload_session_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -330,7 +330,7 @@ TEST(GrpcResumableUploadSessionTest, ResumeFromEmpty) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_resumable_upload_session_url.cc b/google/cloud/storage/internal/grpc_resumable_upload_session_url.cc
index 768e0acb2524e..027bedbd8776c 100644
--- a/google/cloud/storage/internal/grpc_resumable_upload_session_url.cc
+++ b/google/cloud/storage/internal/grpc_resumable_upload_session_url.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 auto constexpr kUriScheme = "grpc://";
@@ -51,7 +51,7 @@ bool IsGrpcResumableSessionUrl(std::string const& upload_session_url) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_resumable_upload_session_url.h b/google/cloud/storage/internal/grpc_resumable_upload_session_url.h
index 3f554fe2c612e..a88e01d25115d 100644
--- a/google/cloud/storage/internal/grpc_resumable_upload_session_url.h
+++ b/google/cloud/storage/internal/grpc_resumable_upload_session_url.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /*
@@ -53,7 +53,7 @@ StatusOr<ResumableUploadSessionGrpcParams> DecodeGrpcResumableUploadSessionUrl(
 bool IsGrpcResumableSessionUrl(std::string const& upload_session_url);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/grpc_resumable_upload_session_url_test.cc b/google/cloud/storage/internal/grpc_resumable_upload_session_url_test.cc
index 8768aabc6ebde..ec65115b7ee18 100644
--- a/google/cloud/storage/internal/grpc_resumable_upload_session_url_test.cc
+++ b/google/cloud/storage/internal/grpc_resumable_upload_session_url_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -47,7 +47,7 @@ TEST(GrpcUploadSessionTest, MalformedUri) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_function.cc b/google/cloud/storage/internal/hash_function.cc
index f758db4ccd7b5..ce96124e61f08 100644
--- a/google/cloud/storage/internal/hash_function.cc
+++ b/google/cloud/storage/internal/hash_function.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 std::unique_ptr<HashFunction> CreateHashFunction(bool disable_crc32c,
@@ -65,7 +65,7 @@ std::unique_ptr<HashFunction> CreateHashFunction(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_function.h b/google/cloud/storage/internal/hash_function.h
index a637829007e0a..2d6e9b359c86c 100644
--- a/google/cloud/storage/internal/hash_function.h
+++ b/google/cloud/storage/internal/hash_function.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Defines the interface to compute hash values during uploads and downloads.
@@ -90,7 +90,7 @@ std::unique_ptr<HashFunction> CreateHashFunction(
     ResumableUploadRequest const& request);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_function_impl.cc b/google/cloud/storage/internal/hash_function_impl.cc
index b459c56f1fce1..3442e52e7c39d 100644
--- a/google/cloud/storage/internal/hash_function_impl.cc
+++ b/google/cloud/storage/internal/hash_function_impl.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::string CompositeFunction::Name() const {
@@ -60,7 +60,7 @@ HashValues Crc32cHashFunction::Finish() && {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_function_impl.h b/google/cloud/storage/internal/hash_function_impl.h
index 0fffac621d6f3..879c561ef52c4 100644
--- a/google/cloud/storage/internal/hash_function_impl.h
+++ b/google/cloud/storage/internal/hash_function_impl.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -95,7 +95,7 @@ class Crc32cHashFunction : public HashFunction {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_function_impl_test.cc b/google/cloud/storage/internal/hash_function_impl_test.cc
index 3286f43ec750e..a8d7f9437273b 100644
--- a/google/cloud/storage/internal/hash_function_impl_test.cc
+++ b/google/cloud/storage/internal/hash_function_impl_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -217,7 +217,7 @@ TEST(HasFunctionImplTest, CreateHashFunctionUploadResumedSession) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_validator.cc b/google/cloud/storage/internal/hash_validator.cc
index 50d91ff846f67..804f86dcfbc04 100644
--- a/google/cloud/storage/internal/hash_validator.cc
+++ b/google/cloud/storage/internal/hash_validator.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -76,7 +76,7 @@ std::string FormatComputedHashes(HashValidator::Result const& result) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_validator.h b/google/cloud/storage/internal/hash_validator.h
index 4b50f4e09778d..94bf0eb81851e 100644
--- a/google/cloud/storage/internal/hash_validator.h
+++ b/google/cloud/storage/internal/hash_validator.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class ObjectMetadata;
 namespace internal {
 /**
@@ -86,7 +86,7 @@ std::string FormatReceivedHashes(HashValidator::Result const& result);
 std::string FormatComputedHashes(HashValidator::Result const& result);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_validator_impl.cc b/google/cloud/storage/internal/hash_validator_impl.cc
index b8ad42eb65ae7..5d81b7d88bed1 100644
--- a/google/cloud/storage/internal/hash_validator_impl.cc
+++ b/google/cloud/storage/internal/hash_validator_impl.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 HashValidator::Result NullHashValidator::Finish(HashValues computed) && {
@@ -88,7 +88,7 @@ HashValidator::Result Crc32cHashValidator::Finish(HashValues computed) && {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_validator_impl.h b/google/cloud/storage/internal/hash_validator_impl.h
index a6a84ae7030a8..d547929616969 100644
--- a/google/cloud/storage/internal/hash_validator_impl.h
+++ b/google/cloud/storage/internal/hash_validator_impl.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class ObjectMetadata;
 namespace internal {
 /**
@@ -96,7 +96,7 @@ class Crc32cHashValidator : public HashValidator {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_validator_test.cc b/google/cloud/storage/internal/hash_validator_test.cc
index 48e9f40090925..9a1b92c1230fa 100644
--- a/google/cloud/storage/internal/hash_validator_test.cc
+++ b/google/cloud/storage/internal/hash_validator_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -293,7 +293,7 @@ TEST(HashValidatorImplTest, CreateHashFunctionUpload) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_values.cc b/google/cloud/storage/internal/hash_values.cc
index 1390cb7dd585e..d26e4e3c398c0 100644
--- a/google/cloud/storage/internal/hash_values.cc
+++ b/google/cloud/storage/internal/hash_values.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::string Format(HashValues const& values) {
@@ -34,7 +34,7 @@ HashValues Merge(HashValues a, HashValues b) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_values.h b/google/cloud/storage/internal/hash_values.h
index 62d3649853e53..0bc3beec79d78 100644
--- a/google/cloud/storage/internal/hash_values.h
+++ b/google/cloud/storage/internal/hash_values.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -42,7 +42,7 @@ std::string Format(HashValues const& values);
 HashValues Merge(HashValues a, HashValues b);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hash_values_test.cc b/google/cloud/storage/internal/hash_values_test.cc
index 95e7d43e1e21b..14511158488ad 100644
--- a/google/cloud/storage/internal/hash_values_test.cc
+++ b/google/cloud/storage/internal/hash_values_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -56,7 +56,7 @@ TEST(HashValuesTest, Merge) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hmac_key_metadata_parser.cc b/google/cloud/storage/internal/hmac_key_metadata_parser.cc
index 220bd028228ae..a22456c429576 100644
--- a/google/cloud/storage/internal/hmac_key_metadata_parser.cc
+++ b/google/cloud/storage/internal/hmac_key_metadata_parser.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<HmacKeyMetadata> HmacKeyMetadataParser::FromJson(
     nlohmann::json const& json) {
@@ -49,7 +49,7 @@ StatusOr<HmacKeyMetadata> HmacKeyMetadataParser::FromString(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hmac_key_metadata_parser.h b/google/cloud/storage/internal/hmac_key_metadata_parser.h
index 6e94f60556610..b826e522a554a 100644
--- a/google/cloud/storage/internal/hmac_key_metadata_parser.h
+++ b/google/cloud/storage/internal/hmac_key_metadata_parser.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct HmacKeyMetadataParser {
   static StatusOr<HmacKeyMetadata> FromJson(nlohmann::json const& json);
@@ -31,7 +31,7 @@ struct HmacKeyMetadataParser {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hmac_key_requests.cc b/google/cloud/storage/internal/hmac_key_requests.cc
index 30f32c5ad005a..c7d7e4bf2f77f 100644
--- a/google/cloud/storage/internal/hmac_key_requests.cc
+++ b/google/cloud/storage/internal/hmac_key_requests.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::ostream& operator<<(std::ostream& os, CreateHmacKeyRequest const& r) {
@@ -112,7 +112,7 @@ std::ostream& operator<<(std::ostream& os, UpdateHmacKeyRequest const& r) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hmac_key_requests.h b/google/cloud/storage/internal/hmac_key_requests.h
index 1459ef9d32520..26654f2f5714e 100644
--- a/google/cloud/storage/internal/hmac_key_requests.h
+++ b/google/cloud/storage/internal/hmac_key_requests.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 template <typename Derived, typename... Options>
@@ -177,7 +177,7 @@ class UpdateHmacKeyRequest
 std::ostream& operator<<(std::ostream& os, UpdateHmacKeyRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hmac_key_requests_test.cc b/google/cloud/storage/internal/hmac_key_requests_test.cc
index 383fce321df5e..b9b4d2a86255a 100644
--- a/google/cloud/storage/internal/hmac_key_requests_test.cc
+++ b/google/cloud/storage/internal/hmac_key_requests_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -258,7 +258,7 @@ TEST(HmacKeysRequestsTest, Update) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/http_response.cc b/google/cloud/storage/internal/http_response.cc
index 2049e418dec59..0b7f30c384a9c 100644
--- a/google/cloud/storage/internal/http_response.cc
+++ b/google/cloud/storage/internal/http_response.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 Status AsStatus(HttpResponse const& http_response) {
@@ -140,7 +140,7 @@ std::ostream& operator<<(std::ostream& os, HttpResponse const& rhs) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/http_response.h b/google/cloud/storage/internal/http_response.h
index 09c65fbb20160..49fb0aaa18ad9 100644
--- a/google/cloud/storage/internal/http_response.h
+++ b/google/cloud/storage/internal/http_response.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 enum HttpStatusCode {
@@ -107,7 +107,7 @@ Status AsStatus(HttpResponse const& http_response);
 std::ostream& operator<<(std::ostream& os, HttpResponse const& rhs);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/http_response_test.cc b/google/cloud/storage/internal/http_response_test.cc
index cefe14e4528cf..1563f4bf6d09b 100644
--- a/google/cloud/storage/internal/http_response_test.cc
+++ b/google/cloud/storage/internal/http_response_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -94,7 +94,7 @@ TEST(HttpResponseTest, AsStatus) {
 }
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hybrid_client.cc b/google/cloud/storage/internal/hybrid_client.cc
index 8bfdfdcc3a7eb..c642fe93a98c4 100644
--- a/google/cloud/storage/internal/hybrid_client.cc
+++ b/google/cloud/storage/internal/hybrid_client.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::shared_ptr<RawClient> HybridClient::Create(Options const& options) {
@@ -302,7 +302,7 @@ StatusOr<EmptyResponse> HybridClient::DeleteNotification(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/hybrid_client.h b/google/cloud/storage/internal/hybrid_client.h
index 02c7bf70dc5ad..678cb76c50d8a 100644
--- a/google/cloud/storage/internal/hybrid_client.h
+++ b/google/cloud/storage/internal/hybrid_client.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 class HybridClient : public RawClient {
@@ -150,7 +150,7 @@ class HybridClient : public RawClient {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/impersonate_service_account_credentials.cc b/google/cloud/storage/internal/impersonate_service_account_credentials.cc
index e50ba7439a0f3..e6098cfabb181 100644
--- a/google/cloud/storage/internal/impersonate_service_account_credentials.cc
+++ b/google/cloud/storage/internal/impersonate_service_account_credentials.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -64,7 +64,7 @@ StatusOr<std::string> ImpersonateServiceAccountCredentials::AuthorizationHeader(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/impersonate_service_account_credentials.h b/google/cloud/storage/internal/impersonate_service_account_credentials.h
index c7ba99a21dc2f..7c3953b8065cd 100644
--- a/google/cloud/storage/internal/impersonate_service_account_credentials.h
+++ b/google/cloud/storage/internal/impersonate_service_account_credentials.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 class ImpersonateServiceAccountCredentials : public oauth2::Credentials {
@@ -49,7 +49,7 @@ class ImpersonateServiceAccountCredentials : public oauth2::Credentials {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/impersonate_service_account_credentials_test.cc b/google/cloud/storage/internal/impersonate_service_account_credentials_test.cc
index 05fbf6eaa5752..d8c834de72f5a 100644
--- a/google/cloud/storage/internal/impersonate_service_account_credentials_test.cc
+++ b/google/cloud/storage/internal/impersonate_service_account_credentials_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -71,7 +71,7 @@ TEST(ImpersonateServiceAccountCredentialsTest, Basic) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
\ No newline at end of file
diff --git a/google/cloud/storage/internal/lifecycle_rule_parser.cc b/google/cloud/storage/internal/lifecycle_rule_parser.cc
index a25e76c9db50c..929246b22703b 100644
--- a/google/cloud/storage/internal/lifecycle_rule_parser.cc
+++ b/google/cloud/storage/internal/lifecycle_rule_parser.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<LifecycleRule> LifecycleRuleParser::FromJson(
     nlohmann::json const& json) {
@@ -105,7 +105,7 @@ StatusOr<LifecycleRule> LifecycleRuleParser::FromString(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/lifecycle_rule_parser.h b/google/cloud/storage/internal/lifecycle_rule_parser.h
index 6ed46c1d2f750..19fe463102482 100644
--- a/google/cloud/storage/internal/lifecycle_rule_parser.h
+++ b/google/cloud/storage/internal/lifecycle_rule_parser.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct LifecycleRuleParser {
   static StatusOr<LifecycleRule> FromJson(nlohmann::json const& json);
@@ -31,7 +31,7 @@ struct LifecycleRuleParser {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/logging_client.cc b/google/cloud/storage/internal/logging_client.cc
index 8f99d5c6d8dba..3149e3aae8960 100644
--- a/google/cloud/storage/internal/logging_client.cc
+++ b/google/cloud/storage/internal/logging_client.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace {
@@ -370,7 +370,7 @@ StatusOr<EmptyResponse> LoggingClient::DeleteNotification(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/logging_client.h b/google/cloud/storage/internal/logging_client.h
index daf1099229831..7015be9a74c9e 100644
--- a/google/cloud/storage/internal/logging_client.h
+++ b/google/cloud/storage/internal/logging_client.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * A decorator for `RawClient` that logs each operation.
@@ -147,7 +147,7 @@ class LoggingClient : public RawClient {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/logging_client_test.cc b/google/cloud/storage/internal/logging_client_test.cc
index ae50027fbe19d..48d4cf2050189 100644
--- a/google/cloud/storage/internal/logging_client_test.cc
+++ b/google/cloud/storage/internal/logging_client_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -229,7 +229,7 @@ TEST_F(LoggingClientTest, ListObjects) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/logging_resumable_upload_session.cc b/google/cloud/storage/internal/logging_resumable_upload_session.cc
index 261a947ba2f5f..168074e8c7b11 100644
--- a/google/cloud/storage/internal/logging_resumable_upload_session.cc
+++ b/google/cloud/storage/internal/logging_resumable_upload_session.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 StatusOr<ResumableUploadResponse> LoggingResumableUploadSession::UploadChunk(
@@ -94,7 +94,7 @@ LoggingResumableUploadSession::last_response() const {
 bool LoggingResumableUploadSession::done() const { return session_->done(); }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/logging_resumable_upload_session.h b/google/cloud/storage/internal/logging_resumable_upload_session.h
index 9825db054627b..91b48200a29c2 100644
--- a/google/cloud/storage/internal/logging_resumable_upload_session.h
+++ b/google/cloud/storage/internal/logging_resumable_upload_session.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * A decorator for `ResumableUploadSession` that logs each operation.
@@ -50,7 +50,7 @@ class LoggingResumableUploadSession : public ResumableUploadSession {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/logging_resumable_upload_session_test.cc b/google/cloud/storage/internal/logging_resumable_upload_session_test.cc
index 1719ea73fe0dd..1d2fce0aa81b1 100644
--- a/google/cloud/storage/internal/logging_resumable_upload_session_test.cc
+++ b/google/cloud/storage/internal/logging_resumable_upload_session_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -150,7 +150,7 @@ TEST_F(LoggingResumableUploadSessionTest, LastResponseBadStatus) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/make_jwt_assertion.cc b/google/cloud/storage/internal/make_jwt_assertion.cc
index 995d2bb19cb43..8fe2ca3b7564f 100644
--- a/google/cloud/storage/internal/make_jwt_assertion.cc
+++ b/google/cloud/storage/internal/make_jwt_assertion.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 StatusOr<std::string> MakeJWTAssertionNoThrow(std::string const& header,
@@ -33,7 +33,7 @@ StatusOr<std::string> MakeJWTAssertionNoThrow(std::string const& header,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/make_jwt_assertion.h b/google/cloud/storage/internal/make_jwt_assertion.h
index 4cfe37384d2be..614241f2f15bc 100644
--- a/google/cloud/storage/internal/make_jwt_assertion.h
+++ b/google/cloud/storage/internal/make_jwt_assertion.h
@@ -22,14 +22,14 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<std::string> MakeJWTAssertionNoThrow(std::string const& header,
                                               std::string const& payload,
                                               std::string const& pem_contents);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/make_jwt_assertion_test.cc b/google/cloud/storage/internal/make_jwt_assertion_test.cc
index a567c5aa14533..8fd9d59be6285 100644
--- a/google/cloud/storage/internal/make_jwt_assertion_test.cc
+++ b/google/cloud/storage/internal/make_jwt_assertion_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -63,7 +63,7 @@ TEST(MakeJWTAssertionNoThrow, InvalidKey) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/metadata_parser.cc b/google/cloud/storage/internal/metadata_parser.cc
index 3723e136f12ab..5dafb4f3307f8 100644
--- a/google/cloud/storage/internal/metadata_parser.cc
+++ b/google/cloud/storage/internal/metadata_parser.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<bool> ParseBoolField(nlohmann::json const& json,
                               char const* field_name) {
@@ -114,7 +114,7 @@ StatusOr<std::chrono::system_clock::time_point> ParseTimestampField(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/metadata_parser.h b/google/cloud/storage/internal/metadata_parser.h
index a925dd9d10cde..15408da72d0be 100644
--- a/google/cloud/storage/internal/metadata_parser.h
+++ b/google/cloud/storage/internal/metadata_parser.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Parses a boolean field, even if it is represented by a string type in the
@@ -79,7 +79,7 @@ StatusOr<std::chrono::system_clock::time_point> ParseTimestampField(
     nlohmann::json const& json, char const* field_name);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/metadata_parser_test.cc b/google/cloud/storage/internal/metadata_parser_test.cc
index 358041d94ddb8..2c07f315165a0 100644
--- a/google/cloud/storage/internal/metadata_parser_test.cc
+++ b/google/cloud/storage/internal/metadata_parser_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -235,7 +235,7 @@ TEST(MetadataParserTest, ParseIntegralFieldInvalidFieldType) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/minimal_iam_credentials_rest.cc b/google/cloud/storage/internal/minimal_iam_credentials_rest.cc
index 9bc402bec6434..5258fd62b33b4 100644
--- a/google/cloud/storage/internal/minimal_iam_credentials_rest.cc
+++ b/google/cloud/storage/internal/minimal_iam_credentials_rest.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace {
@@ -147,7 +147,7 @@ std::shared_ptr<MinimalIamCredentialsRest> MakeMinimalIamCredentialsRestStub(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/minimal_iam_credentials_rest.h b/google/cloud/storage/internal/minimal_iam_credentials_rest.h
index aada09db72891..2c256ff1c2195 100644
--- a/google/cloud/storage/internal/minimal_iam_credentials_rest.h
+++ b/google/cloud/storage/internal/minimal_iam_credentials_rest.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 struct GenerateAccessTokenRequest {
@@ -49,7 +49,7 @@ std::shared_ptr<MinimalIamCredentialsRest> MakeMinimalIamCredentialsRestStub(
     std::shared_ptr<oauth2::Credentials> credentials, Options options = {});
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/notification_metadata_parser.cc b/google/cloud/storage/internal/notification_metadata_parser.cc
index 9e063b456f35f..39f33344ef795 100644
--- a/google/cloud/storage/internal/notification_metadata_parser.cc
+++ b/google/cloud/storage/internal/notification_metadata_parser.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<NotificationMetadata> NotificationMetadataParser::FromJson(
     nlohmann::json const& json) {
@@ -58,7 +58,7 @@ StatusOr<NotificationMetadata> NotificationMetadataParser::FromString(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/notification_metadata_parser.h b/google/cloud/storage/internal/notification_metadata_parser.h
index 9e304f837643c..c895ae8dd9952 100644
--- a/google/cloud/storage/internal/notification_metadata_parser.h
+++ b/google/cloud/storage/internal/notification_metadata_parser.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct NotificationMetadataParser {
   static StatusOr<NotificationMetadata> FromJson(nlohmann::json const& json);
@@ -30,7 +30,7 @@ struct NotificationMetadataParser {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/notification_requests.cc b/google/cloud/storage/internal/notification_requests.cc
index efa16ceaca767..07b4494e609e3 100644
--- a/google/cloud/storage/internal/notification_requests.cc
+++ b/google/cloud/storage/internal/notification_requests.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 std::ostream& operator<<(std::ostream& os, ListNotificationsRequest const& r) {
   os << "ListNotificationsRequest={bucket_name=" << r.bucket_name();
@@ -73,7 +73,7 @@ std::ostream& operator<<(std::ostream& os, DeleteNotificationRequest const& r) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/notification_requests.h b/google/cloud/storage/internal/notification_requests.h
index edd6f64d82a10..9401584623b86 100644
--- a/google/cloud/storage/internal/notification_requests.h
+++ b/google/cloud/storage/internal/notification_requests.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// Represents a request to call the `BucketAccessControls: list` API.
 class ListNotificationsRequest
@@ -121,7 +121,7 @@ class DeleteNotificationRequest
 std::ostream& operator<<(std::ostream& os, DeleteNotificationRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/notification_requests_test.cc b/google/cloud/storage/internal/notification_requests_test.cc
index 29a1321e2a0a7..72c55935d8bfe 100644
--- a/google/cloud/storage/internal/notification_requests_test.cc
+++ b/google/cloud/storage/internal/notification_requests_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -187,7 +187,7 @@ TEST(NotificationRequestTest, Delete) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_access_control_parser.cc b/google/cloud/storage/internal/object_access_control_parser.cc
index 37352f524d967..a2f8cb6e2fe63 100644
--- a/google/cloud/storage/internal/object_access_control_parser.cc
+++ b/google/cloud/storage/internal/object_access_control_parser.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<ObjectAccessControl> ObjectAccessControlParser::FromJson(
     nlohmann::json const& json) {
@@ -44,7 +44,7 @@ StatusOr<ObjectAccessControl> ObjectAccessControlParser::FromString(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_access_control_parser.h b/google/cloud/storage/internal/object_access_control_parser.h
index f88f86366ed2e..3c9df583197f6 100644
--- a/google/cloud/storage/internal/object_access_control_parser.h
+++ b/google/cloud/storage/internal/object_access_control_parser.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct ObjectAccessControlParser {
   static StatusOr<ObjectAccessControl> FromJson(nlohmann::json const& json);
@@ -31,7 +31,7 @@ struct ObjectAccessControlParser {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_acl_requests.cc b/google/cloud/storage/internal/object_acl_requests.cc
index f8466e43c0f61..5a1a90c58be19 100644
--- a/google/cloud/storage/internal/object_acl_requests.cc
+++ b/google/cloud/storage/internal/object_acl_requests.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 std::ostream& operator<<(std::ostream& os, ListObjectAclRequest const& r) {
   os << "ListObjectAclRequest={bucket_name=" << r.bucket_name()
@@ -112,7 +112,7 @@ std::ostream& operator<<(std::ostream& os, PatchObjectAclRequest const& r) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_acl_requests.h b/google/cloud/storage/internal/object_acl_requests.h
index 13860786211a6..ed30efa108366 100644
--- a/google/cloud/storage/internal/object_acl_requests.h
+++ b/google/cloud/storage/internal/object_acl_requests.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Represents a request for the `ObjectAccessControls: list` API.
@@ -166,7 +166,7 @@ class PatchObjectAclRequest
 std::ostream& operator<<(std::ostream& os, PatchObjectAclRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_acl_requests_test.cc b/google/cloud/storage/internal/object_acl_requests_test.cc
index 43367ba74f9bb..c626ab9072971 100644
--- a/google/cloud/storage/internal/object_acl_requests_test.cc
+++ b/google/cloud/storage/internal/object_acl_requests_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -297,7 +297,7 @@ TEST(PatchObjectAclRequestTest, PatchStream) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_metadata_parser.cc b/google/cloud/storage/internal/object_metadata_parser.cc
index 2a6b78591e840..fc1a565dc3aab 100644
--- a/google/cloud/storage/internal/object_metadata_parser.cc
+++ b/google/cloud/storage/internal/object_metadata_parser.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 /**
@@ -216,7 +216,7 @@ nlohmann::json ObjectMetadataJsonForUpdate(ObjectMetadata const& meta) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_metadata_parser.h b/google/cloud/storage/internal/object_metadata_parser.h
index 095811ce07b3b..250a1b5324f73 100644
--- a/google/cloud/storage/internal/object_metadata_parser.h
+++ b/google/cloud/storage/internal/object_metadata_parser.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct ObjectMetadataParser {
   static StatusOr<ObjectMetadata> FromJson(nlohmann::json const& json);
@@ -47,7 +47,7 @@ nlohmann::json ObjectMetadataJsonForUpdate(ObjectMetadata const& meta);
 //@}
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_read_source.h b/google/cloud/storage/internal/object_read_source.h
index 5c37f654ef2e5..9d65d1fae408c 100644
--- a/google/cloud/storage/internal/object_read_source.h
+++ b/google/cloud/storage/internal/object_read_source.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * The result of reading some data from the source.
@@ -96,7 +96,7 @@ class ObjectReadErrorSource : public ObjectReadSource {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_read_streambuf.cc b/google/cloud/storage/internal/object_read_streambuf.cc
index c5d254188d003..1945f0121e0dd 100644
--- a/google/cloud/storage/internal/object_read_streambuf.cc
+++ b/google/cloud/storage/internal/object_read_streambuf.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 ObjectReadStreambuf::ObjectReadStreambuf(
@@ -200,7 +200,7 @@ std::streamsize ObjectReadStreambuf::xsgetn(char* s, std::streamsize count) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_read_streambuf.h b/google/cloud/storage/internal/object_read_streambuf.h
index 64cbe6f9a615d..d83aa943a5fb9 100644
--- a/google/cloud/storage/internal/object_read_streambuf.h
+++ b/google/cloud/storage/internal/object_read_streambuf.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -91,7 +91,7 @@ class ObjectReadStreambuf : public std::basic_streambuf<char> {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_read_streambuf_test.cc b/google/cloud/storage/internal/object_read_streambuf_test.cc
index ebcc2de82b921..9a108a19b4db9 100644
--- a/google/cloud/storage/internal/object_read_streambuf_test.cc
+++ b/google/cloud/storage/internal/object_read_streambuf_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -93,7 +93,7 @@ TEST(ObjectReadStreambufTest, WrongSeek) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_requests.cc b/google/cloud/storage/internal/object_requests.cc
index 520d0d74d57cf..ef4eaa3965792 100644
--- a/google/cloud/storage/internal/object_requests.cc
+++ b/google/cloud/storage/internal/object_requests.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 std::string UpdateObjectRequest::json_payload() const {
   return ObjectMetadataJsonForUpdate(metadata_).dump();
@@ -414,7 +414,7 @@ std::ostream& operator<<(std::ostream& os,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_requests.h b/google/cloud/storage/internal/object_requests.h
index 5ea2043056ffb..ee42dc95e7266 100644
--- a/google/cloud/storage/internal/object_requests.h
+++ b/google/cloud/storage/internal/object_requests.h
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Represents a request to the `Objects: list` API.
@@ -437,7 +437,7 @@ std::ostream& operator<<(std::ostream& os,
                          QueryResumableUploadRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_requests_test.cc b/google/cloud/storage/internal/object_requests_test.cc
index 32e43687b086b..852c1aaaed8fa 100644
--- a/google/cloud/storage/internal/object_requests_test.cc
+++ b/google/cloud/storage/internal/object_requests_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -860,7 +860,7 @@ TEST(DefaultCtorsWork, Trivial) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_write_streambuf.cc b/google/cloud/storage/internal/object_write_streambuf.cc
index c161e77bc4e56..7f0a8b0a377a3 100644
--- a/google/cloud/storage/internal/object_write_streambuf.cc
+++ b/google/cloud/storage/internal/object_write_streambuf.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 ObjectWriteStreambuf::ObjectWriteStreambuf(
@@ -227,7 +227,7 @@ void ObjectWriteStreambuf::FlushRoundChunk(ConstBufferSequence buffers) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_write_streambuf.h b/google/cloud/storage/internal/object_write_streambuf.h
index fe1346452a2c2..f67be07f7e039 100644
--- a/google/cloud/storage/internal/object_write_streambuf.h
+++ b/google/cloud/storage/internal/object_write_streambuf.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 class ObjectWriteStream;
 namespace internal {
 
@@ -123,7 +123,7 @@ class ObjectWriteStreambuf : public std::basic_streambuf<char> {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/object_write_streambuf_test.cc b/google/cloud/storage/internal/object_write_streambuf_test.cc
index 0b7d29e1bcc2a..f89c143e2816c 100644
--- a/google/cloud/storage/internal/object_write_streambuf_test.cc
+++ b/google/cloud/storage/internal/object_write_streambuf_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -696,7 +696,7 @@ TEST(ObjectWriteStreambufTest, PubsyncTooSmall) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/openssl_util.cc b/google/cloud/storage/internal/openssl_util.cc
index d3f92a22cbf59..b6066fddb70c7 100644
--- a/google/cloud/storage/internal/openssl_util.cc
+++ b/google/cloud/storage/internal/openssl_util.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace {
@@ -186,7 +186,7 @@ std::vector<std::uint8_t> MD5Hash(std::string const& payload) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/openssl_util.h b/google/cloud/storage/internal/openssl_util.h
index e1c9ecac05dc9..2b9d01f10837e 100644
--- a/google/cloud/storage/internal/openssl_util.h
+++ b/google/cloud/storage/internal/openssl_util.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /**
@@ -82,7 +82,7 @@ StatusOr<std::vector<std::uint8_t>> UrlsafeBase64Decode(std::string const& str);
 std::vector<std::uint8_t> MD5Hash(std::string const& payload);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/openssl_util_test.cc b/google/cloud/storage/internal/openssl_util_test.cc
index 8b247dd64197f..0e8b2698e490e 100644
--- a/google/cloud/storage/internal/openssl_util_test.cc
+++ b/google/cloud/storage/internal/openssl_util_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -103,7 +103,7 @@ TEST(OpensslUtilTest, MD5HashSimple) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/parameter_pack_validation.h b/google/cloud/storage/internal/parameter_pack_validation.h
index 7e368bd4ae3bb..1f7b36bf2ab35 100644
--- a/google/cloud/storage/internal/parameter_pack_validation.h
+++ b/google/cloud/storage/internal/parameter_pack_validation.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 // Check if a parameter pack contains a type
@@ -31,7 +31,7 @@ constexpr bool ContainsType() {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/parameter_pack_validation_test.cc b/google/cloud/storage/internal/parameter_pack_validation_test.cc
index 6ca9aa5cd4134..54081f08cc0b8 100644
--- a/google/cloud/storage/internal/parameter_pack_validation_test.cc
+++ b/google/cloud/storage/internal/parameter_pack_validation_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -31,7 +31,7 @@ TEST(ContainsType, Static) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/patch_builder.cc b/google/cloud/storage/internal/patch_builder.cc
index 1b65c415a37e2..21420bab213f0 100644
--- a/google/cloud/storage/internal/patch_builder.cc
+++ b/google/cloud/storage/internal/patch_builder.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct PatchBuilder::Impl {
  public:
@@ -238,7 +238,7 @@ PatchBuilder& PatchBuilder::SetArrayField(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/patch_builder.h b/google/cloud/storage/internal/patch_builder.h
index 6bb477f274c69..564a20504d432 100644
--- a/google/cloud/storage/internal/patch_builder.h
+++ b/google/cloud/storage/internal/patch_builder.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Prepares a patch for the '<Resource Type>: patch' APIs in Google Cloud
@@ -127,7 +127,7 @@ class PatchBuilder {
   std::unique_ptr<Impl> pimpl_;
 };
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/patch_builder_test.cc b/google/cloud/storage/internal/patch_builder_test.cc
index 1ae4bb631e8ce..fda73336e9c6c 100644
--- a/google/cloud/storage/internal/patch_builder_test.cc
+++ b/google/cloud/storage/internal/patch_builder_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 TEST(PatchBuilderTest, Empty) {
@@ -159,7 +159,7 @@ TEST(PatchBuilderTest, SetArrayField) {
 }
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/policy_document_request.cc b/google/cloud/storage/internal/policy_document_request.cc
index 78c1b2ee05b31..c50282b2b52f7 100644
--- a/google/cloud/storage/internal/policy_document_request.cc
+++ b/google/cloud/storage/internal/policy_document_request.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -274,7 +274,7 @@ std::ostream& operator<<(std::ostream& os, PolicyDocumentV4Request const& r) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/policy_document_request.h b/google/cloud/storage/internal/policy_document_request.h
index c8d67c7455e80..090b6e2f8a75a 100644
--- a/google/cloud/storage/internal/policy_document_request.h
+++ b/google/cloud/storage/internal/policy_document_request.h
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 StatusOr<std::string> PostPolicyV4Escape(std::string const& utf8_bytes);
@@ -153,7 +153,7 @@ class PolicyDocumentV4Request {
 std::ostream& operator<<(std::ostream& os, PolicyDocumentV4Request const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/policy_document_request_test.cc b/google/cloud/storage/internal/policy_document_request_test.cc
index bb9330c016af9..d20a59336848c 100644
--- a/google/cloud/storage/internal/policy_document_request_test.cc
+++ b/google/cloud/storage/internal/policy_document_request_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -130,7 +130,7 @@ TEST(PolicyDocumentV4Request, RequiredFormFields) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/raw_client.cc b/google/cloud/storage/internal/raw_client.cc
index 9e9f4cdeb2660..763bb0290e81d 100644
--- a/google/cloud/storage/internal/raw_client.cc
+++ b/google/cloud/storage/internal/raw_client.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 StatusOr<std::unique_ptr<ResumableUploadSession>>
@@ -26,7 +26,7 @@ RawClient::RestoreResumableSession(std::string const& /*session_id*/) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/raw_client.h b/google/cloud/storage/internal/raw_client.h
index 6edf5e502918c..1cb3a0bcdd1de 100644
--- a/google/cloud/storage/internal/raw_client.h
+++ b/google/cloud/storage/internal/raw_client.h
@@ -41,7 +41,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 class ObjectReadStreambuf;
 class ObjectWriteStreambuf;
@@ -185,7 +185,7 @@ class RawClient {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/raw_client_wrapper_utils.h b/google/cloud/storage/internal/raw_client_wrapper_utils.h
index 2d8f0e01b73a1..573c165f6ef06 100644
--- a/google/cloud/storage/internal/raw_client_wrapper_utils.h
+++ b/google/cloud/storage/internal/raw_client_wrapper_utils.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Defines types to wrap `RawClient` function calls.
@@ -66,7 +66,7 @@ struct Signature<StatusOr<Response> (
 
 }  // namespace raw_client_wrapper_utils
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/resumable_upload_session.cc b/google/cloud/storage/internal/resumable_upload_session.cc
index 7e973ee48ae8b..bd60807960e22 100644
--- a/google/cloud/storage/internal/resumable_upload_session.cc
+++ b/google/cloud/storage/internal/resumable_upload_session.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<ResumableUploadResponse> ResumableUploadResponse::FromHttpResponse(
     HttpResponse response) {
@@ -112,7 +112,7 @@ std::ostream& operator<<(std::ostream& os, ResumableUploadResponse const& r) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/resumable_upload_session.h b/google/cloud/storage/internal/resumable_upload_session.h
index 4f1d53e95b6c4..69e51dca8d4dc 100644
--- a/google/cloud/storage/internal/resumable_upload_session.h
+++ b/google/cloud/storage/internal/resumable_upload_session.h
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct ResumableUploadResponse;
 
@@ -160,7 +160,7 @@ class ResumableUploadSessionError : public ResumableUploadSession {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/resumable_upload_session_test.cc b/google/cloud/storage/internal/resumable_upload_session_test.cc
index 4ec651ae37afd..d9fd39307c3aa 100644
--- a/google/cloud/storage/internal/resumable_upload_session_test.cc
+++ b/google/cloud/storage/internal/resumable_upload_session_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -142,7 +142,7 @@ TEST(ResumableUploadResponseTest, NegativeEnd) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_client.cc b/google/cloud/storage/internal/retry_client.cc
index b366fcc35fc13..75aa7828c7f9b 100644
--- a/google/cloud/storage/internal/retry_client.cc
+++ b/google/cloud/storage/internal/retry_client.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -708,7 +708,7 @@ StatusOr<EmptyResponse> RetryClient::DeleteNotification(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_client.h b/google/cloud/storage/internal/retry_client.h
index bcab9c39dc1a6..faafc5989ad77 100644
--- a/google/cloud/storage/internal/retry_client.h
+++ b/google/cloud/storage/internal/retry_client.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Decorates a `RawClient` to retry each operation.
@@ -161,7 +161,7 @@ class RetryClient : public RawClient,
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_client_test.cc b/google/cloud/storage/internal/retry_client_test.cc
index 47c8fb221843f..ebf45242356be 100644
--- a/google/cloud/storage/internal/retry_client_test.cc
+++ b/google/cloud/storage/internal/retry_client_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -114,7 +114,7 @@ TEST_F(RetryClientTest, ExpiredRetryPolicy) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_object_read_source.cc b/google/cloud/storage/internal/retry_object_read_source.cc
index 2586564475938..a784aeb793034 100644
--- a/google/cloud/storage/internal/retry_object_read_source.cc
+++ b/google/cloud/storage/internal/retry_object_read_source.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::uint64_t InitialOffset(OffsetDirection const& offset_direction,
@@ -124,7 +124,7 @@ StatusOr<ReadSourceResult> RetryObjectReadSource::Read(char* buf,
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_object_read_source.h b/google/cloud/storage/internal/retry_object_read_source.h
index b44d96abbecb1..5c5d6ab40a90d 100644
--- a/google/cloud/storage/internal/retry_object_read_source.h
+++ b/google/cloud/storage/internal/retry_object_read_source.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 enum OffsetDirection { kFromBeginning, kFromEnd };
@@ -60,7 +60,7 @@ class RetryObjectReadSource : public ObjectReadSource {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_object_read_source_test.cc b/google/cloud/storage/internal/retry_object_read_source_test.cc
index 9889b3eff9fd9..92f5d42d99770 100644
--- a/google/cloud/storage/internal/retry_object_read_source_test.cc
+++ b/google/cloud/storage/internal/retry_object_read_source_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -330,7 +330,7 @@ TEST(RetryObjectReadSourceTest, TransientFailureWithGeneration) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_resumable_upload_session.cc b/google/cloud/storage/internal/retry_resumable_upload_session.cc
index 41ddcce4c0026..cc5e94387d8d3 100644
--- a/google/cloud/storage/internal/retry_resumable_upload_session.cc
+++ b/google/cloud/storage/internal/retry_resumable_upload_session.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace {
@@ -185,7 +185,7 @@ RetryResumableUploadSession::last_response() const {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_resumable_upload_session.h b/google/cloud/storage/internal/retry_resumable_upload_session.h
index 3651b35d2054a..8a72160bac2ef 100644
--- a/google/cloud/storage/internal/retry_resumable_upload_session.h
+++ b/google/cloud/storage/internal/retry_resumable_upload_session.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Decorates a `ResumableUploadSession` to retry operations that fail.
@@ -76,7 +76,7 @@ class RetryResumableUploadSession : public ResumableUploadSession {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/retry_resumable_upload_session_test.cc b/google/cloud/storage/internal/retry_resumable_upload_session_test.cc
index ef18c2b94270c..2df6a4159fced 100644
--- a/google/cloud/storage/internal/retry_resumable_upload_session_test.cc
+++ b/google/cloud/storage/internal/retry_resumable_upload_session_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -1088,7 +1088,7 @@ TEST_F(RetryResumableUploadSessionTest, ShortWriteRetrySucceeds) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/self_signing_service_account_credentials.cc b/google/cloud/storage/internal/self_signing_service_account_credentials.cc
index 5aa174b6fdfee..dcc2fd7c7d4f2 100644
--- a/google/cloud/storage/internal/self_signing_service_account_credentials.cc
+++ b/google/cloud/storage/internal/self_signing_service_account_credentials.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 auto constexpr kExpiration = std::chrono::hours(1);
@@ -80,7 +80,7 @@ std::string SelfSigningServiceAccountCredentials::KeyId() const {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/self_signing_service_account_credentials.h b/google/cloud/storage/internal/self_signing_service_account_credentials.h
index ce104e48919ef..c737ff95a98f2 100644
--- a/google/cloud/storage/internal/self_signing_service_account_credentials.h
+++ b/google/cloud/storage/internal/self_signing_service_account_credentials.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 struct SelfSigningServiceAccountCredentialsInfo {
@@ -60,7 +60,7 @@ class SelfSigningServiceAccountCredentials
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/self_signing_service_account_credentials_test.cc b/google/cloud/storage/internal/self_signing_service_account_credentials_test.cc
index f1aa3106440af..d36e17693c2e8 100644
--- a/google/cloud/storage/internal/self_signing_service_account_credentials_test.cc
+++ b/google/cloud/storage/internal/self_signing_service_account_credentials_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -101,7 +101,7 @@ TEST(SelfSigningServiceAccountCredentials, Basic) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/service_account_parser.cc b/google/cloud/storage/internal/service_account_parser.cc
index 01784d0267e40..63bac34f837e9 100644
--- a/google/cloud/storage/internal/service_account_parser.cc
+++ b/google/cloud/storage/internal/service_account_parser.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 StatusOr<ServiceAccount> ServiceAccountParser::FromJson(
     nlohmann::json const& json) {
@@ -37,7 +37,7 @@ StatusOr<ServiceAccount> ServiceAccountParser::FromString(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/service_account_parser.h b/google/cloud/storage/internal/service_account_parser.h
index fb60affe6e405..e9bd27c95b418 100644
--- a/google/cloud/storage/internal/service_account_parser.h
+++ b/google/cloud/storage/internal/service_account_parser.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct ServiceAccountParser {
   static StatusOr<ServiceAccount> FromJson(nlohmann::json const& json);
@@ -31,7 +31,7 @@ struct ServiceAccountParser {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/service_account_requests.cc b/google/cloud/storage/internal/service_account_requests.cc
index babf40c60676c..62fab1bb5cf54 100644
--- a/google/cloud/storage/internal/service_account_requests.cc
+++ b/google/cloud/storage/internal/service_account_requests.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 std::ostream& operator<<(std::ostream& os,
                          GetProjectServiceAccountRequest const& r) {
@@ -27,7 +27,7 @@ std::ostream& operator<<(std::ostream& os,
   return os << "}";
 }
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/service_account_requests.h b/google/cloud/storage/internal/service_account_requests.h
index fb678b5727d7d..baf6316122a68 100644
--- a/google/cloud/storage/internal/service_account_requests.h
+++ b/google/cloud/storage/internal/service_account_requests.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Requests the Google Cloud Storage service account for a project.
@@ -46,7 +46,7 @@ std::ostream& operator<<(std::ostream& os,
                          GetProjectServiceAccountRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/service_account_requests_test.cc b/google/cloud/storage/internal/service_account_requests_test.cc
index ccd509fd1be75..6be187c736d56 100644
--- a/google/cloud/storage/internal/service_account_requests_test.cc
+++ b/google/cloud/storage/internal/service_account_requests_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -38,7 +38,7 @@ TEST(ServiceAccountRequests, Get) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/sha256_hash.cc b/google/cloud/storage/internal/sha256_hash.cc
index f3429d2bb0bae..02ceaff421edb 100644
--- a/google/cloud/storage/internal/sha256_hash.cc
+++ b/google/cloud/storage/internal/sha256_hash.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 namespace {
@@ -76,7 +76,7 @@ std::vector<std::uint8_t> HexDecode(std::string const& str) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/sha256_hash.h b/google/cloud/storage/internal/sha256_hash.h
index 365b6d2b3d6b1..5203c2f68900d 100644
--- a/google/cloud/storage/internal/sha256_hash.h
+++ b/google/cloud/storage/internal/sha256_hash.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /// Return the SHA256 hash (as raw bytes) of @p str.
@@ -39,7 +39,7 @@ std::string HexEncode(std::vector<std::uint8_t> const& bytes);
 std::vector<std::uint8_t> HexDecode(std::string const& str);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/sha256_hash_test.cc b/google/cloud/storage/internal/sha256_hash_test.cc
index b7a95ac146eef..904ebb1d54d65 100644
--- a/google/cloud/storage/internal/sha256_hash_test.cc
+++ b/google/cloud/storage/internal/sha256_hash_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -58,7 +58,7 @@ TEST(Sha256Hash, Simple) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/sign_blob_requests.cc b/google/cloud/storage/internal/sign_blob_requests.cc
index 3525f0b213b66..746c9a9e4b4e9 100644
--- a/google/cloud/storage/internal/sign_blob_requests.cc
+++ b/google/cloud/storage/internal/sign_blob_requests.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::ostream& operator<<(std::ostream& os, SignBlobRequest const& r) {
@@ -46,7 +46,7 @@ std::ostream& operator<<(std::ostream& os, SignBlobResponse const& r) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/sign_blob_requests.h b/google/cloud/storage/internal/sign_blob_requests.h
index 38922d9d128c8..a79578f9d0463 100644
--- a/google/cloud/storage/internal/sign_blob_requests.h
+++ b/google/cloud/storage/internal/sign_blob_requests.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Represents a request to call the `projects.serviceAccounts.signBlob` API.
@@ -80,7 +80,7 @@ struct SignBlobResponse {
 std::ostream& operator<<(std::ostream& os, SignBlobResponse const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/sign_blob_requests_test.cc b/google/cloud/storage/internal/sign_blob_requests_test.cc
index 0149d6582eeee..6827c58378e98 100644
--- a/google/cloud/storage/internal/sign_blob_requests_test.cc
+++ b/google/cloud/storage/internal/sign_blob_requests_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -76,7 +76,7 @@ TEST(SignBlobRequestsTest, ResponseIOStream) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/signed_url_requests.cc b/google/cloud/storage/internal/signed_url_requests.cc
index 8bcf429b4b746..d2fad6110e6a7 100644
--- a/google/cloud/storage/internal/signed_url_requests.cc
+++ b/google/cloud/storage/internal/signed_url_requests.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 void SignUrlRequestCommon::SetOption(AddExtensionHeaderOption const& o) {
@@ -316,7 +316,7 @@ std::ostream& operator<<(std::ostream& os, V4SignUrlRequest const& r) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/signed_url_requests.h b/google/cloud/storage/internal/signed_url_requests.h
index 8ff3a2200ae98..40f3407c6c905 100644
--- a/google/cloud/storage/internal/signed_url_requests.h
+++ b/google/cloud/storage/internal/signed_url_requests.h
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// The common data for SignUrlRequests.
 class SignUrlRequestCommon {
@@ -334,7 +334,7 @@ class V4SignUrlRequest {
 std::ostream& operator<<(std::ostream& os, V4SignUrlRequest const& r);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/signed_url_requests_test.cc b/google/cloud/storage/internal/signed_url_requests_test.cc
index e6d1c385b93da..8d49e9f476e0c 100644
--- a/google/cloud/storage/internal/signed_url_requests_test.cc
+++ b/google/cloud/storage/internal/signed_url_requests_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -656,7 +656,7 @@ TEST(DefaultCtorsWork, Trivial) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/storage_auth.cc b/google/cloud/storage/internal/storage_auth.cc
index caa10c823db17..9c4542f5d7215 100644
--- a/google/cloud/storage/internal/storage_auth.cc
+++ b/google/cloud/storage/internal/storage_auth.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::unique_ptr<StorageStub::ReadObjectStream> StorageAuth::ReadObject(
@@ -59,7 +59,7 @@ StorageAuth::QueryWriteStatus(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/storage_auth.h b/google/cloud/storage/internal/storage_auth.h
index 26226aea9f406..aeea3559eddfb 100644
--- a/google/cloud/storage/internal/storage_auth.h
+++ b/google/cloud/storage/internal/storage_auth.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 class StorageAuth : public StorageStub {
@@ -54,7 +54,7 @@ class StorageAuth : public StorageStub {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/storage_auth_test.cc b/google/cloud/storage/internal/storage_auth_test.cc
index d0c8ced40ca67..1cf5cadeea375 100644
--- a/google/cloud/storage/internal/storage_auth_test.cc
+++ b/google/cloud/storage/internal/storage_auth_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -126,7 +126,7 @@ TEST(StorageAuthTest, QueryWriteStatus) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/storage_round_robin.cc b/google/cloud/storage/internal/storage_round_robin.cc
index 3d69924b3c0bc..6426369e5fee5 100644
--- a/google/cloud/storage/internal/storage_round_robin.cc
+++ b/google/cloud/storage/internal/storage_round_robin.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::unique_ptr<StorageStub::ReadObjectStream> StorageRoundRobin::ReadObject(
@@ -53,7 +53,7 @@ std::shared_ptr<StorageStub> StorageRoundRobin::Child() {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/storage_round_robin.h b/google/cloud/storage/internal/storage_round_robin.h
index 5b6db74749ef7..9bde57c4a1bda 100644
--- a/google/cloud/storage/internal/storage_round_robin.h
+++ b/google/cloud/storage/internal/storage_round_robin.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 class StorageRoundRobin : public StorageStub {
@@ -56,7 +56,7 @@ class StorageRoundRobin : public StorageStub {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/storage_round_robin_test.cc b/google/cloud/storage/internal/storage_round_robin_test.cc
index c865f40315dc3..929055ec7533f 100644
--- a/google/cloud/storage/internal/storage_round_robin_test.cc
+++ b/google/cloud/storage/internal/storage_round_robin_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -146,7 +146,7 @@ TEST(StorageAuthTest, QueryWriteStatus) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/storage_stub.cc b/google/cloud/storage/internal/storage_stub.cc
index 9ccd87a52df19..6e5286a33d4ad 100644
--- a/google/cloud/storage/internal/storage_stub.cc
+++ b/google/cloud/storage/internal/storage_stub.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -85,7 +85,7 @@ std::shared_ptr<StorageStub> MakeDefaultStorageStub(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/storage_stub.h b/google/cloud/storage/internal/storage_stub.h
index c214b74c3e474..1055d8822a551 100644
--- a/google/cloud/storage/internal/storage_stub.h
+++ b/google/cloud/storage/internal/storage_stub.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 class StorageStub {
@@ -58,7 +58,7 @@ std::shared_ptr<StorageStub> MakeDefaultStorageStub(
     std::shared_ptr<grpc::Channel> channel);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/tuple_filter.h b/google/cloud/storage/internal/tuple_filter.h
index bafb8365d72bf..943959001abea 100644
--- a/google/cloud/storage/internal/tuple_filter.h
+++ b/google/cloud/storage/internal/tuple_filter.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 /// Prepend a type to tuple's type list - unmatched case.
@@ -168,7 +168,7 @@ struct NotAmong {
 };
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/tuple_filter_test.cc b/google/cloud/storage/internal/tuple_filter_test.cc
index 0bf57e3bb6a11..632f31b718455 100644
--- a/google/cloud/storage/internal/tuple_filter_test.cc
+++ b/google/cloud/storage/internal/tuple_filter_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 TEST(TupleFilter, EmptyTuple) {
@@ -104,7 +104,7 @@ TEST(TupleFilter, TupleByReference) {
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/unified_rest_credentials.cc b/google/cloud/storage/internal/unified_rest_credentials.cc
index e0b3707610cc9..f120d8fa9c92e 100644
--- a/google/cloud/storage/internal/unified_rest_credentials.cc
+++ b/google/cloud/storage/internal/unified_rest_credentials.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 using ::google::cloud::internal::AccessTokenConfig;
@@ -73,7 +73,7 @@ std::shared_ptr<oauth2::Credentials> MapCredentials(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/unified_rest_credentials.h b/google/cloud/storage/internal/unified_rest_credentials.h
index 755d25ac3e8ff..c0c724c2b9d65 100644
--- a/google/cloud/storage/internal/unified_rest_credentials.h
+++ b/google/cloud/storage/internal/unified_rest_credentials.h
@@ -23,14 +23,14 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 std::shared_ptr<oauth2::Credentials> MapCredentials(
     std::shared_ptr<google::cloud::Credentials> const& credentials);
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/internal/unified_rest_credentials_test.cc b/google/cloud/storage/internal/unified_rest_credentials_test.cc
index 6b7ba552d7be1..76ced3ffe1337 100644
--- a/google/cloud/storage/internal/unified_rest_credentials_test.cc
+++ b/google/cloud/storage/internal/unified_rest_credentials_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -119,7 +119,7 @@ TEST_F(UnifiedRestCredentialsTest, LoadSuccess) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/lifecycle_rule.cc b/google/cloud/storage/lifecycle_rule.cc
index 186a626f51c55..3398cef4891f1 100644
--- a/google/cloud/storage/lifecycle_rule.cc
+++ b/google/cloud/storage/lifecycle_rule.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::ostream& operator<<(std::ostream& os, LifecycleRuleAction const& rhs) {
   return os << "LifecycleRuleAction={" << rhs.type << ", " << rhs.storage_class
             << "}";
@@ -202,7 +202,7 @@ std::ostream& operator<<(std::ostream& os, LifecycleRule const& rhs) {
             << ", action=" << rhs.action() << "}";
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/lifecycle_rule.h b/google/cloud/storage/lifecycle_rule.h
index 9438428bf2c3d..e7c828d417878 100644
--- a/google/cloud/storage/lifecycle_rule.h
+++ b/google/cloud/storage/lifecycle_rule.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct LifecycleRuleParser;
 class GrpcClient;
@@ -355,7 +355,7 @@ inline bool operator>=(LifecycleRule const& lhs, LifecycleRule const& rhs) {
 }
 
 std::ostream& operator<<(std::ostream& os, LifecycleRule const& rhs);
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/lifecycle_rule_test.cc b/google/cloud/storage/lifecycle_rule_test.cc
index e75f09de1eaae..2a67c85d7671a 100644
--- a/google/cloud/storage/lifecycle_rule_test.cc
+++ b/google/cloud/storage/lifecycle_rule_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::ElementsAre;
@@ -482,7 +482,7 @@ TEST(LifecycleRuleTest, LifecycleRuleStream) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_buckets_reader.cc b/google/cloud/storage/list_buckets_reader.cc
index 9414507de5e3f..08cff5cebfa88 100644
--- a/google/cloud/storage/list_buckets_reader.cc
+++ b/google/cloud/storage/list_buckets_reader.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // ListBucketsReader::iterator must satisfy the requirements of an
 // InputIterator.
 static_assert(
@@ -59,7 +59,7 @@ static_assert(
     "++it when it is of ListBucketsReader::iterator type must be a "
     "ListBucketsReader::iterator &>");
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_buckets_reader.h b/google/cloud/storage/list_buckets_reader.h
index 5f66721e3729c..d78608f3b9216 100644
--- a/google/cloud/storage/list_buckets_reader.h
+++ b/google/cloud/storage/list_buckets_reader.h
@@ -23,14 +23,14 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ListBucketsReader =
     google::cloud::internal::PaginationRange<BucketMetadata>;
 
 using ListBucketsIterator = ListBucketsReader::iterator;
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_buckets_reader_test.cc b/google/cloud/storage/list_buckets_reader_test.cc
index 6c32e50143f6e..cc6dbc4fd80a4 100644
--- a/google/cloud/storage/list_buckets_reader_test.cc
+++ b/google/cloud/storage/list_buckets_reader_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::internal::ListBucketsRequest;
@@ -157,7 +157,7 @@ TEST(ListBucketsReaderTest, PermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_hmac_keys_reader.cc b/google/cloud/storage/list_hmac_keys_reader.cc
index 118e21a35360c..03b915376dd8e 100644
--- a/google/cloud/storage/list_hmac_keys_reader.cc
+++ b/google/cloud/storage/list_hmac_keys_reader.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // ListHmacKeysReader::iterator must satisfy the requirements of an
 // InputIterator.
 static_assert(
@@ -61,7 +61,7 @@ static_assert(
     "++it when it is of ListHmacKeysReader::iterator type must be a "
     "ListHmacKeysReader::iterator &>");
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_hmac_keys_reader.h b/google/cloud/storage/list_hmac_keys_reader.h
index 5964e094e24eb..c7726135a1dbc 100644
--- a/google/cloud/storage/list_hmac_keys_reader.h
+++ b/google/cloud/storage/list_hmac_keys_reader.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /**
  * A range to paginate over the HmacKeys for a project.
@@ -35,7 +35,7 @@ using ListHmacKeysReader =
 
 using ListHmacKeysIterator = ListHmacKeysReader::iterator;
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_hmac_keys_reader_test.cc b/google/cloud/storage/list_hmac_keys_reader_test.cc
index bba44ef83db42..f0777c960c3ad 100644
--- a/google/cloud/storage/list_hmac_keys_reader_test.cc
+++ b/google/cloud/storage/list_hmac_keys_reader_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::internal::ListHmacKeysRequest;
@@ -167,7 +167,7 @@ TEST(ListHmacKeysReaderTest, PermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_objects_and_prefixes_reader.h b/google/cloud/storage/list_objects_and_prefixes_reader.h
index f3fd334b50fa5..f8d1c99a6c2ba 100644
--- a/google/cloud/storage/list_objects_and_prefixes_reader.h
+++ b/google/cloud/storage/list_objects_and_prefixes_reader.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 using ObjectOrPrefix = absl::variant<ObjectMetadata, std::string>;
 
 using ListObjectsAndPrefixesReader =
@@ -47,7 +47,7 @@ inline void SortObjectsAndPrefixes(std::vector<ObjectOrPrefix>& in) {
 }
 }  // namespace internal
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_objects_and_prefixes_reader_test.cc b/google/cloud/storage/list_objects_and_prefixes_reader_test.cc
index ab471f20bf804..2560c896c07ba 100644
--- a/google/cloud/storage/list_objects_and_prefixes_reader_test.cc
+++ b/google/cloud/storage/list_objects_and_prefixes_reader_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::internal::ListObjectsRequest;
@@ -105,7 +105,7 @@ TEST(ListObjectsAndPrefixesReaderTest, Basic) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_objects_reader.cc b/google/cloud/storage/list_objects_reader.cc
index 1637f1217096a..96e2fe801035f 100644
--- a/google/cloud/storage/list_objects_reader.cc
+++ b/google/cloud/storage/list_objects_reader.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 // ListObjectsReader::iterator must satisfy the requirements of an
 // InputIterator.
 static_assert(
@@ -59,7 +59,7 @@ static_assert(
     "++it when it is of ListObjectsReader::iterator type must be a "
     "ListObjectsReader::iterator &>");
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_objects_reader.h b/google/cloud/storage/list_objects_reader.h
index 9528ac30ac8a1..e5233378d0980 100644
--- a/google/cloud/storage/list_objects_reader.h
+++ b/google/cloud/storage/list_objects_reader.h
@@ -25,14 +25,14 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ListObjectsReader =
     google::cloud::internal::PaginationRange<ObjectMetadata>;
 
 using ListObjectsIterator = ListObjectsReader::iterator;
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/list_objects_reader_test.cc b/google/cloud/storage/list_objects_reader_test.cc
index dd4100d5f6b37..308fdadc49867 100644
--- a/google/cloud/storage/list_objects_reader_test.cc
+++ b/google/cloud/storage/list_objects_reader_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::internal::ListObjectsRequest;
@@ -159,7 +159,7 @@ TEST(ListObjectsReaderTest, PermanentFailure) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/notification_event_type.h b/google/cloud/storage/notification_event_type.h
index 0859169725907..b0dfb647c90c0 100644
--- a/google/cloud/storage/notification_event_type.h
+++ b/google/cloud/storage/notification_event_type.h
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// Contains functions to return well-known notification event type names.
 namespace event_type {
 inline char const* ObjectFinalize() {
@@ -44,7 +44,7 @@ inline char const* ObjectArchive() {
 }
 
 }  // namespace event_type
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/notification_metadata.cc b/google/cloud/storage/notification_metadata.cc
index dc6038287ad9e..753d06c051876 100644
--- a/google/cloud/storage/notification_metadata.cc
+++ b/google/cloud/storage/notification_metadata.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::string NotificationMetadata::JsonPayloadForInsert() const {
   // Required fields, always include them, even if empty.
   nlohmann::json json{
@@ -77,7 +77,7 @@ std::ostream& operator<<(std::ostream& os, NotificationMetadata const& rhs) {
             << "}";
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/notification_metadata.h b/google/cloud/storage/notification_metadata.h
index 550fafd030cbd..4880eed3a61b5 100644
--- a/google/cloud/storage/notification_metadata.h
+++ b/google/cloud/storage/notification_metadata.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct NotificationMetadataParser;
 }  // namespace internal
@@ -200,7 +200,7 @@ inline bool operator>=(NotificationMetadata const& lhs,
 
 std::ostream& operator<<(std::ostream& os, NotificationMetadata const& rhs);
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/notification_metadata_test.cc b/google/cloud/storage/notification_metadata_test.cc
index ac3cfaeacc64c..789314a088b24 100644
--- a/google/cloud/storage/notification_metadata_test.cc
+++ b/google/cloud/storage/notification_metadata_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::HasSubstr;
@@ -192,7 +192,7 @@ TEST(NotificationMetadataTest, SetTopic) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/notification_payload_format.h b/google/cloud/storage/notification_payload_format.h
index facb83ebdf339..c3ed68f2e9cce 100644
--- a/google/cloud/storage/notification_payload_format.h
+++ b/google/cloud/storage/notification_payload_format.h
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// Contains functions to return well-known notification payload format names.
 namespace payload_format {
 inline char const* JsonApiV1() {
@@ -34,7 +34,7 @@ inline char const* None() {
 }
 
 }  // namespace payload_format
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/anonymous_credentials.cc b/google/cloud/storage/oauth2/anonymous_credentials.cc
index 59906914e8b00..24da82d6d3fc3 100644
--- a/google/cloud/storage/oauth2/anonymous_credentials.cc
+++ b/google/cloud/storage/oauth2/anonymous_credentials.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 StatusOr<std::string> AnonymousCredentials::AuthorizationHeader() {
@@ -25,7 +25,7 @@ StatusOr<std::string> AnonymousCredentials::AuthorizationHeader() {
 }
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/anonymous_credentials.h b/google/cloud/storage/oauth2/anonymous_credentials.h
index cc56046cb719d..e1c8abce7fe94 100644
--- a/google/cloud/storage/oauth2/anonymous_credentials.h
+++ b/google/cloud/storage/oauth2/anonymous_credentials.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 /**
@@ -47,7 +47,7 @@ class AnonymousCredentials : public Credentials {
 };
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/anonymous_credentials_test.cc b/google/cloud/storage/oauth2/anonymous_credentials_test.cc
index 19429b89b751d..528e7cff245ea 100644
--- a/google/cloud/storage/oauth2/anonymous_credentials_test.cc
+++ b/google/cloud/storage/oauth2/anonymous_credentials_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 namespace {
 
@@ -35,7 +35,7 @@ TEST_F(AnonymousCredentialsTest, AuthorizationHeaderReturnsEmptyString) {
 
 }  // namespace
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/authorized_user_credentials.cc b/google/cloud/storage/oauth2/authorized_user_credentials.cc
index 90120b76a298b..869e380e7595d 100644
--- a/google/cloud/storage/oauth2/authorized_user_credentials.cc
+++ b/google/cloud/storage/oauth2/authorized_user_credentials.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 StatusOr<AuthorizedUserCredentialsInfo> ParseAuthorizedUserCredentials(
     std::string const& content, std::string const& source,
@@ -87,7 +87,7 @@ ParseAuthorizedUserRefreshResponse(
                                                       new_expiration};
 }
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/authorized_user_credentials.h b/google/cloud/storage/oauth2/authorized_user_credentials.h
index a48435c548fb2..d40fb6fe682fa 100644
--- a/google/cloud/storage/oauth2/authorized_user_credentials.h
+++ b/google/cloud/storage/oauth2/authorized_user_credentials.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 /// Object to hold information used to instantiate an AuthorizedUserCredentials.
 struct AuthorizedUserCredentialsInfo {
@@ -118,7 +118,7 @@ class AuthorizedUserCredentials : public Credentials {
 };
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/authorized_user_credentials_test.cc b/google/cloud/storage/oauth2/authorized_user_credentials_test.cc
index c748c10b3c7ea..c86882b04b75c 100644
--- a/google/cloud/storage/oauth2/authorized_user_credentials_test.cc
+++ b/google/cloud/storage/oauth2/authorized_user_credentials_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 namespace {
 
@@ -407,7 +407,7 @@ TEST_F(AuthorizedUserCredentialsTest, ParseAuthorizedUserRefreshResponse) {
 
 }  // namespace
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/compute_engine_credentials.cc b/google/cloud/storage/oauth2/compute_engine_credentials.cc
index 2e182b92497c1..b5d69408091ca 100644
--- a/google/cloud/storage/oauth2/compute_engine_credentials.cc
+++ b/google/cloud/storage/oauth2/compute_engine_credentials.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 StatusOr<ServiceAccountMetadata> ParseMetadataServerResponse(
     storage::internal::HttpResponse const& response) {
@@ -75,7 +75,7 @@ ParseComputeEngineRefreshResponse(
 }
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/compute_engine_credentials.h b/google/cloud/storage/oauth2/compute_engine_credentials.h
index 454d5ea3ab48f..efffd54077a7f 100644
--- a/google/cloud/storage/oauth2/compute_engine_credentials.h
+++ b/google/cloud/storage/oauth2/compute_engine_credentials.h
@@ -33,7 +33,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 /// A helper struct that contains service account metadata.
 struct ServiceAccountMetadata {
@@ -201,7 +201,7 @@ class ComputeEngineCredentials : public Credentials {
 };
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/compute_engine_credentials_test.cc b/google/cloud/storage/oauth2/compute_engine_credentials_test.cc
index 774abd2569b4d..044eb014be350 100644
--- a/google/cloud/storage/oauth2/compute_engine_credentials_test.cc
+++ b/google/cloud/storage/oauth2/compute_engine_credentials_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 namespace {
 
@@ -400,7 +400,7 @@ TEST_F(ComputeEngineCredentialsTest, AccountEmail) {
 
 }  // namespace
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/credential_constants.h b/google/cloud/storage/oauth2/credential_constants.h
index 7c21b18d58603..3a7231393ac3e 100644
--- a/google/cloud/storage/oauth2/credential_constants.h
+++ b/google/cloud/storage/oauth2/credential_constants.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 /**
@@ -64,7 +64,7 @@ inline char const* GoogleOAuthScopeCloudPlatform() {
   return kScope;
 }
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/credentials.cc b/google/cloud/storage/oauth2/credentials.cc
index 2bd1eb10050fd..83a21ae78c94a 100644
--- a/google/cloud/storage/oauth2/credentials.cc
+++ b/google/cloud/storage/oauth2/credentials.cc
@@ -17,7 +17,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 StatusOr<std::vector<std::uint8_t>> Credentials::SignBlob(
@@ -27,7 +27,7 @@ StatusOr<std::vector<std::uint8_t>> Credentials::SignBlob(
 }
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/credentials.h b/google/cloud/storage/oauth2/credentials.h
index 928859c6cbf90..52d0ecc3445f6 100644
--- a/google/cloud/storage/oauth2/credentials.h
+++ b/google/cloud/storage/oauth2/credentials.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 /**
  * Interface for OAuth 2.0 credentials used to access Google Cloud services.
@@ -71,7 +71,7 @@ class Credentials {
 };
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/google_application_default_credentials_file.cc b/google/cloud/storage/oauth2/google_application_default_credentials_file.cc
index 21a6d3fca8b2e..95829343012f0 100644
--- a/google/cloud/storage/oauth2/google_application_default_credentials_file.cc
+++ b/google/cloud/storage/oauth2/google_application_default_credentials_file.cc
@@ -34,7 +34,7 @@ std::string const& GoogleWellKnownAdcFilePathSuffix() {
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 std::string GoogleAdcFilePathFromEnvVarOrEmpty() {
@@ -62,7 +62,7 @@ std::string GoogleAdcFilePathFromWellKnownPathOrEmpty() {
 }
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/google_application_default_credentials_file.h b/google/cloud/storage/oauth2/google_application_default_credentials_file.h
index be1b9ec2522b9..cba7b4dca1a39 100644
--- a/google/cloud/storage/oauth2/google_application_default_credentials_file.h
+++ b/google/cloud/storage/oauth2/google_application_default_credentials_file.h
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 /**
@@ -82,7 +82,7 @@ inline char const* GoogleAdcHomeEnvVar() {
 }
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/google_application_default_credentials_file_test.cc b/google/cloud/storage/oauth2/google_application_default_credentials_file_test.cc
index cdff91775a761..fa7e26a4027e8 100644
--- a/google/cloud/storage/oauth2/google_application_default_credentials_file_test.cc
+++ b/google/cloud/storage/oauth2/google_application_default_credentials_file_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 namespace {
 
@@ -76,7 +76,7 @@ TEST_F(DefaultServiceAccountFileTest, HomeNotSet) {
 
 }  // namespace
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/google_credentials.cc b/google/cloud/storage/oauth2/google_credentials.cc
index 19fddd8045c5d..7b04dbe76bbd5 100644
--- a/google/cloud/storage/oauth2/google_credentials.cc
+++ b/google/cloud/storage/oauth2/google_credentials.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 char constexpr kAdcLink[] =
@@ -331,7 +331,7 @@ std::shared_ptr<Credentials> CreateComputeEngineCredentials(
 }
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/google_credentials.h b/google/cloud/storage/oauth2/google_credentials.h
index a24afd9669555..5b0ba2393d573 100644
--- a/google/cloud/storage/oauth2/google_credentials.h
+++ b/google/cloud/storage/oauth2/google_credentials.h
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 /**
@@ -280,7 +280,7 @@ std::shared_ptr<Credentials> CreateComputeEngineCredentials(
 //@}
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/google_credentials_test.cc b/google/cloud/storage/oauth2/google_credentials_test.cc
index 76be0cd1a1d40..805fca3e355c2 100644
--- a/google/cloud/storage/oauth2/google_credentials_test.cc
+++ b/google/cloud/storage/oauth2/google_credentials_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 namespace {
 
@@ -528,7 +528,7 @@ TEST_F(GoogleCredentialsTest, LoadP12Credentials) {
 
 }  // namespace
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/refreshing_credentials_wrapper.cc b/google/cloud/storage/oauth2/refreshing_credentials_wrapper.cc
index 951470bfea539..bb1bea9c2d02c 100644
--- a/google/cloud/storage/oauth2/refreshing_credentials_wrapper.cc
+++ b/google/cloud/storage/oauth2/refreshing_credentials_wrapper.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 bool RefreshingCredentialsWrapper::IsExpired(
@@ -33,7 +33,7 @@ bool RefreshingCredentialsWrapper::IsValid(
 }
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/refreshing_credentials_wrapper.h b/google/cloud/storage/oauth2/refreshing_credentials_wrapper.h
index 6ae0414b47cf2..f4de24cb2cfc8 100644
--- a/google/cloud/storage/oauth2/refreshing_credentials_wrapper.h
+++ b/google/cloud/storage/oauth2/refreshing_credentials_wrapper.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 /**
@@ -80,7 +80,7 @@ class RefreshingCredentialsWrapper {
 };
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/service_account_credentials.cc b/google/cloud/storage/oauth2/service_account_credentials.cc
index e2d52a2bb0177..09abfb9bfae20 100644
--- a/google/cloud/storage/oauth2/service_account_credentials.cc
+++ b/google/cloud/storage/oauth2/service_account_credentials.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 
 StatusOr<ServiceAccountCredentialsInfo> ParseServiceAccountCredentials(
@@ -273,7 +273,7 @@ ParseServiceAccountRefreshResponse(
 }
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/service_account_credentials.h b/google/cloud/storage/oauth2/service_account_credentials.h
index 707b4e145e310..09d5df01d7ca5 100644
--- a/google/cloud/storage/oauth2/service_account_credentials.h
+++ b/google/cloud/storage/oauth2/service_account_credentials.h
@@ -37,7 +37,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 namespace oauth2 {
 /// Object to hold information used to instantiate an ServiceAccountCredentials.
@@ -206,7 +206,7 @@ class ServiceAccountCredentials : public Credentials {
 };
 
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/oauth2/service_account_credentials_test.cc b/google/cloud/storage/oauth2/service_account_credentials_test.cc
index b861746ab19ab..50711db439dd5 100644
--- a/google/cloud/storage/oauth2/service_account_credentials_test.cc
+++ b/google/cloud/storage/oauth2/service_account_credentials_test.cc
@@ -34,7 +34,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace oauth2 {
 namespace {
 
@@ -792,7 +792,7 @@ TEST_F(ServiceAccountCredentialsTest, ParseServiceAccountRefreshResponse) {
 
 }  // namespace
 }  // namespace oauth2
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_access_control.cc b/google/cloud/storage/object_access_control.cc
index ff7c45a99c918..570a295c68953 100644
--- a/google/cloud/storage/object_access_control.cc
+++ b/google/cloud/storage/object_access_control.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 bool operator==(ObjectAccessControl const& lhs,
                 ObjectAccessControl const& rhs) {
   // Start with id, generation, object, bucket, etag because they should fail
@@ -44,7 +44,7 @@ std::ostream& operator<<(std::ostream& os, ObjectAccessControl const& rhs) {
   return os << ", role=" << rhs.role() << ", self_link=" << rhs.self_link()
             << "}";
 }
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_access_control.h b/google/cloud/storage/object_access_control.h
index 522b4a8f2af29..41ff9a955cf98 100644
--- a/google/cloud/storage/object_access_control.h
+++ b/google/cloud/storage/object_access_control.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct ObjectAccessControlParser;
 class GrpcClient;
@@ -141,7 +141,7 @@ class ObjectAccessControlPatchBuilder {
   internal::PatchBuilder impl_;
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_access_control_test.cc b/google/cloud/storage/object_access_control_test.cc
index 39c5741e6ded0..04abd73b9be68 100644
--- a/google/cloud/storage/object_access_control_test.cc
+++ b/google/cloud/storage/object_access_control_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 /// @test Verify ObjectAccessControl::set_entity() works as expected.
@@ -69,7 +69,7 @@ TEST(ObjectAccessControlTest, Compare) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_metadata.cc b/google/cloud/storage/object_metadata.cc
index db73cd138089b..afab9ddbaa8e2 100644
--- a/google/cloud/storage/object_metadata.cc
+++ b/google/cloud/storage/object_metadata.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 using ::google::cloud::internal::FormatRfc3339;
 
@@ -257,7 +257,7 @@ ObjectMetadataPatchBuilder& ObjectMetadataPatchBuilder::ResetCustomTime() {
   return *this;
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_metadata.h b/google/cloud/storage/object_metadata.h
index fe9695bf0cbc9..0a0e944f4549c 100644
--- a/google/cloud/storage/object_metadata.h
+++ b/google/cloud/storage/object_metadata.h
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct ObjectMetadataParser;
 class GrpcClient;
@@ -359,7 +359,7 @@ struct WithObjectMetadata
   static char const* name() { return "object-metadata"; }
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_metadata_test.cc b/google/cloud/storage/object_metadata_test.cc
index b555f3a3dd542..eecd239a4f87c 100644
--- a/google/cloud/storage/object_metadata_test.cc
+++ b/google/cloud/storage/object_metadata_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 ObjectMetadata CreateObjectMetadataForTest() {
@@ -733,7 +733,7 @@ TEST(ObjectMetadataPatchBuilder, ResetCustomTime) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_read_stream.cc b/google/cloud/storage/object_read_stream.cc
index baeb7af850467..5aebfa072d766 100644
--- a/google/cloud/storage/object_read_stream.cc
+++ b/google/cloud/storage/object_read_stream.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 std::unique_ptr<internal::ObjectReadStreambuf> MakeErrorStreambuf() {
   return absl::make_unique<internal::ObjectReadStreambuf>(
@@ -80,7 +80,7 @@ void ObjectReadStream::Close() {
   }
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_read_stream.h b/google/cloud/storage/object_read_stream.h
index d84c08844a8c0..efb5e2ea27149 100644
--- a/google/cloud/storage/object_read_stream.h
+++ b/google/cloud/storage/object_read_stream.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Represents the headers returned in a streaming upload or download operation.
 using HeadersMap = std::multimap<std::string, std::string>;
@@ -143,7 +143,7 @@ class ObjectReadStream : public std::basic_istream<char> {
   std::unique_ptr<internal::ObjectReadStreambuf> buf_;
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_rewriter.cc b/google/cloud/storage/object_rewriter.cc
index 3f5bbae9febb5..09bde330461f4 100644
--- a/google/cloud/storage/object_rewriter.cc
+++ b/google/cloud/storage/object_rewriter.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 ObjectRewriter::ObjectRewriter(std::shared_ptr<internal::RawClient> client,
                                internal::RewriteObjectRequest request)
     : client_(std::move(client)),
@@ -43,7 +43,7 @@ StatusOr<RewriteProgress> ObjectRewriter::Iterate() {
   return progress_;
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_rewriter.h b/google/cloud/storage/object_rewriter.h
index 236904cc41e0f..473c2fd751a26 100644
--- a/google/cloud/storage/object_rewriter.h
+++ b/google/cloud/storage/object_rewriter.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Represents the status of a rewrite operation.
  *
@@ -135,7 +135,7 @@ class ObjectRewriter {
   ObjectMetadata result_;
   Status last_error_;
 };
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_stream_test.cc b/google/cloud/storage/object_stream_test.cc
index eed87649ea0ea..a5069f71c47fd 100644
--- a/google/cloud/storage/object_stream_test.cc
+++ b/google/cloud/storage/object_stream_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -110,7 +110,7 @@ TEST(ObjectStream, Suspend) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_test.cc b/google/cloud/storage/object_test.cc
index ccb49fd469936..92fefe91d3107 100644
--- a/google/cloud/storage/object_test.cc
+++ b/google/cloud/storage/object_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::canonical_errors::PermanentError;
@@ -894,7 +894,7 @@ TEST_F(ObjectTest, ComposeManyLockingPrefixFails) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_write_stream.cc b/google/cloud/storage/object_write_stream.cc
index bb120d7fb22ae..128377bd7ae37 100644
--- a/google/cloud/storage/object_write_stream.cc
+++ b/google/cloud/storage/object_write_stream.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 std::unique_ptr<internal::ObjectWriteStreambuf> MakeErrorStreambuf() {
   return absl::make_unique<internal::ObjectWriteStreambuf>(
@@ -108,7 +108,7 @@ void ObjectWriteStream::Suspend() && {
   tmp.buf_.reset();
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/object_write_stream.h b/google/cloud/storage/object_write_stream.h
index bbe71c7a0ebc1..9dd4226f23be0 100644
--- a/google/cloud/storage/object_write_stream.h
+++ b/google/cloud/storage/object_write_stream.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 
 /// Represents the headers returned in a streaming upload or download operation.
 using HeadersMap = std::multimap<std::string, std::string>;
@@ -306,7 +306,7 @@ class ObjectWriteStream : public std::basic_ostream<char> {
   std::string payload_;
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/options.h b/google/cloud/storage/options.h
index fcbe54bbecaa4..b60a0725ddaf7 100644
--- a/google/cloud/storage/options.h
+++ b/google/cloud/storage/options.h
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage_experimental {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Set the HTTP version used by the client.
  *
@@ -47,11 +47,11 @@ inline namespace STORAGE_CLIENT_NS {
 struct HttpVersionOption {
   using Type = std::string;
 };
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage_experimental
 
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// This is only intended for testing against staging or development versions
 /// of the service. It is not for public use.
@@ -250,7 +250,7 @@ using ClientOptionList = ::google::cloud::OptionList<
     IdempotencyPolicyOption, CARootsFilePathOption,
     storage_experimental::HttpVersionOption>;
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/override_default_project.h b/google/cloud/storage/override_default_project.h
index f6558c5d05435..8568c08bbfb98 100644
--- a/google/cloud/storage/override_default_project.h
+++ b/google/cloud/storage/override_default_project.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Override the default project.
  *
@@ -39,7 +39,7 @@ struct OverrideDefaultProject
   static char const* name() { return "override_default_project"; }
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/parallel_upload.cc b/google/cloud/storage/parallel_upload.cc
index da3455394453c..1f8000a6537d2 100644
--- a/google/cloud/storage/parallel_upload.cc
+++ b/google/cloud/storage/parallel_upload.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 
 class ParallelObjectWriteStreambuf : public ObjectWriteStreambuf {
@@ -455,7 +455,7 @@ StatusOr<std::pair<std::string, std::int64_t>> ParseResumableSessionId(
 }
 
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/parallel_upload.h b/google/cloud/storage/parallel_upload.h
index 84970e39bb39a..a362e98b490b4 100644
--- a/google/cloud/storage/parallel_upload.h
+++ b/google/cloud/storage/parallel_upload.h
@@ -37,7 +37,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * A parameter type indicating the maximum number of streams to
  * `ParallelUploadFile`.
@@ -1188,7 +1188,7 @@ StatusOr<ObjectMetadata> ParallelUploadFile(
   return res;
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/parallel_uploads_test.cc b/google/cloud/storage/parallel_uploads_test.cc
index a84d36935cea7..eb927d4d25f38 100644
--- a/google/cloud/storage/parallel_uploads_test.cc
+++ b/google/cloud/storage/parallel_uploads_test.cc
@@ -35,7 +35,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -1868,7 +1868,7 @@ TEST_F(ParallelUploadTest, SuspendUploadFileResumeBadOffset) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/policy_document.cc b/google/cloud/storage/policy_document.cc
index beda25cea1677..5c1efd3aa6f97 100644
--- a/google/cloud/storage/policy_document.cc
+++ b/google/cloud/storage/policy_document.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::ostream& operator<<(std::ostream& os, PolicyDocumentCondition const& rhs) {
   return os << "PolicyDocumentCondition=["
             << absl::StrJoin(rhs.elements(), ", ") << "]";
@@ -75,7 +75,7 @@ std::ostream& operator<<(std::ostream& os, PolicyDocumentV4Result const& rhs) {
             << ", policy=" << rhs.policy << ", signature=" << rhs.signature
             << ", signing_algorithm=" << rhs.signing_algorithm << "}";
 }
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/policy_document.h b/google/cloud/storage/policy_document.h
index 44c3adfd982c8..6610dbea35194 100644
--- a/google/cloud/storage/policy_document.h
+++ b/google/cloud/storage/policy_document.h
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define a condition for a policy document.
  */
@@ -204,7 +204,7 @@ std::string FormatDateForForm(PolicyDocumentV4Result const&);
 
 std::ostream& operator<<(std::ostream& os, PolicyDocumentV4Result const& rhs);
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/policy_document_test.cc b/google/cloud/storage/policy_document_test.cc
index 71237e6f471fb..5137a72455bde 100644
--- a/google/cloud/storage/policy_document_test.cc
+++ b/google/cloud/storage/policy_document_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::IsSubsetOf;
@@ -222,7 +222,7 @@ TEST(PolicyDocumentTests, PolicyDocumentV4CtorDefaultTime) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/retry_policy.h b/google/cloud/storage/retry_policy.h
index d60eb0d9b83aa..b00169a32ea01 100644
--- a/google/cloud/storage/retry_policy.h
+++ b/google/cloud/storage/retry_policy.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /// Defines what error codes are permanent errors.
 struct StatusTraits {
@@ -56,7 +56,7 @@ using BackoffPolicy = ::google::cloud::internal::BackoffPolicy;
 using ExponentialBackoffPolicy =
     ::google::cloud::internal::ExponentialBackoffPolicy;
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/retry_policy_test.cc b/google/cloud/storage/retry_policy_test.cc
index 80c8b4e4337fb..994a62b0bd7c2 100644
--- a/google/cloud/storage/retry_policy_test.cc
+++ b/google/cloud/storage/retry_policy_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -54,7 +54,7 @@ TEST(RetryPolicyTest, PermanentFailure) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/service_account.cc b/google/cloud/storage/service_account.cc
index 9aeae39994e41..4f1c85196951e 100644
--- a/google/cloud/storage/service_account.cc
+++ b/google/cloud/storage/service_account.cc
@@ -17,12 +17,12 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::ostream& operator<<(std::ostream& os, ServiceAccount const& rhs) {
   return os << "ServiceAccount={email_address=" << rhs.email_address()
             << ", kind=" << rhs.kind() << "}";
 }
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/service_account.h b/google/cloud/storage/service_account.h
index 97a84a3650348..5ec0e5afce087 100644
--- a/google/cloud/storage/service_account.h
+++ b/google/cloud/storage/service_account.h
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 struct ServiceAccountParser;
 }  // namespace internal
@@ -72,7 +72,7 @@ inline bool operator>=(ServiceAccount const& lhs, ServiceAccount const& rhs) {
 
 std::ostream& operator<<(std::ostream& os, ServiceAccount const& rhs);
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/service_account_test.cc b/google/cloud/storage/service_account_test.cc
index df4ee100cbb94..a3e290604bbab 100644
--- a/google/cloud/storage/service_account_test.cc
+++ b/google/cloud/storage/service_account_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -60,7 +60,7 @@ TEST(ServiceAccountTest, IOStream) {
   EXPECT_THAT(actual, HasSubstr("service-123@example.com"));
 }
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/signed_url_options.h b/google/cloud/storage/signed_url_options.h
index beb79896bfce7..738b93e98e3e0 100644
--- a/google/cloud/storage/signed_url_options.h
+++ b/google/cloud/storage/signed_url_options.h
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Define the expiration time for a signed URL.
  */
@@ -269,7 +269,7 @@ inline AddExtensionFieldOption AddExtensionField(std::string field,
   return AddExtensionFieldOption(std::move(field), std::move(value));
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/signed_url_options_test.cc b/google/cloud/storage/signed_url_options_test.cc
index 662ed2bb7eb93..74aa26362dc62 100644
--- a/google/cloud/storage/signed_url_options_test.cc
+++ b/google/cloud/storage/signed_url_options_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 TEST(SignedUrlOptions, QueryParameters) {
   auto mp = [](char const* k, char const* v) {
@@ -47,7 +47,7 @@ TEST(SignedUrlOptions, QueryParameters) {
             WithUserProject("test-project").value());
 }
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/storage_class.h b/google/cloud/storage/storage_class.h
index 41a4ab75bf55a..eba36b580c62a 100644
--- a/google/cloud/storage/storage_class.h
+++ b/google/cloud/storage/storage_class.h
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /// Contains functions to return well-known storage class names.
 namespace storage_class {
 inline char const* Standard() {
@@ -59,7 +59,7 @@ inline char const* Archive() {
 }
 
 }  // namespace storage_class
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/storage_class_test.cc b/google/cloud/storage/storage_class_test.cc
index 4de4d5d7ba0a7..5eed88d5aca17 100644
--- a/google/cloud/storage/storage_class_test.cc
+++ b/google/cloud/storage/storage_class_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace storage_class {
 namespace {
 
@@ -36,7 +36,7 @@ TEST(StorageClassTest, Values) {
 
 }  // namespace
 }  // namespace storage_class
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/storage_iam_policy_test.cc b/google/cloud/storage/storage_iam_policy_test.cc
index 8704cc372cc8b..37c43c673ca1e 100644
--- a/google/cloud/storage/storage_iam_policy_test.cc
+++ b/google/cloud/storage/storage_iam_policy_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 static_assert(std::is_copy_constructible<NativeExpression>::value,
@@ -464,7 +464,7 @@ TEST(NativeIamPolicy, Printing) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/storage_version_test.cc b/google/cloud/storage/storage_version_test.cc
index 10c0b3527c048..c8f04bc9cf7ea 100644
--- a/google/cloud/storage/storage_version_test.cc
+++ b/google/cloud/storage/storage_version_test.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::HasSubstr;
@@ -53,7 +53,7 @@ TEST(StorageVersionTest, NoBuildInfoInRelease) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/alternative_endpoint_integration_test.cc b/google/cloud/storage/tests/alternative_endpoint_integration_test.cc
index b4c679d1ed481..4d9b7de57e986 100644
--- a/google/cloud/storage/tests/alternative_endpoint_integration_test.cc
+++ b/google/cloud/storage/tests/alternative_endpoint_integration_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::GetEnv;
@@ -135,7 +135,7 @@ TEST_F(AlternativeEndpointIntegrationTest, Write) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/auto_finalize_integration_test.cc b/google/cloud/storage/tests/auto_finalize_integration_test.cc
index 26ed4fcce632f..7507417142d4f 100644
--- a/google/cloud/storage/tests/auto_finalize_integration_test.cc
+++ b/google/cloud/storage/tests/auto_finalize_integration_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -139,7 +139,7 @@ TEST_F(AutoFinalizeIntegrationTest, Disabled) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/bucket_integration_test.cc b/google/cloud/storage/tests/bucket_integration_test.cc
index 3e059bf18b898..d455970392553 100644
--- a/google/cloud/storage/tests/bucket_integration_test.cc
+++ b/google/cloud/storage/tests/bucket_integration_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::AclEntityNames;
@@ -1246,7 +1246,7 @@ TEST_F(BucketIntegrationTest, NativeIamWithRequestedPolicyVersion) {
   ASSERT_STATUS_OK(status);
 }
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/create_client_integration_test.cc b/google/cloud/storage/tests/create_client_integration_test.cc
index a6f1aa2fc7786..f2ca0813a29b7 100644
--- a/google/cloud/storage/tests/create_client_integration_test.cc
+++ b/google/cloud/storage/tests/create_client_integration_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::GetEnv;
@@ -86,7 +86,7 @@ TEST_F(CreateClientIntegrationTest, SettingPolicies) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/curl_download_request_integration_test.cc b/google/cloud/storage/tests/curl_download_request_integration_test.cc
index 3100b1bcd504d..ddb6ceff5178e 100644
--- a/google/cloud/storage/tests/curl_download_request_integration_test.cc
+++ b/google/cloud/storage/tests/curl_download_request_integration_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -398,7 +398,7 @@ TEST(CurlDownloadRequestTest, HttpVersion) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/curl_request_integration_test.cc b/google/cloud/storage/tests/curl_request_integration_test.cc
index 54223385d4c66..f02557e172465 100644
--- a/google/cloud/storage/tests/curl_request_integration_test.cc
+++ b/google/cloud/storage/tests/curl_request_integration_test.cc
@@ -28,7 +28,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -657,7 +657,7 @@ TEST(CurlRequestTest, HandlesReusedOnSuccess) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/curl_resumable_upload_session_integration_test.cc b/google/cloud/storage/tests/curl_resumable_upload_session_integration_test.cc
index 7454d9b819f32..bc8d11905101a 100644
--- a/google/cloud/storage/tests/curl_resumable_upload_session_integration_test.cc
+++ b/google/cloud/storage/tests/curl_resumable_upload_session_integration_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -277,7 +277,7 @@ TEST_F(CurlResumableUploadIntegrationTest, ResetWithParameters) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/curl_sign_blob_integration_test.cc b/google/cloud/storage/tests/curl_sign_blob_integration_test.cc
index 846e9f4d097a2..11151ac208d65 100644
--- a/google/cloud/storage/tests/curl_sign_blob_integration_test.cc
+++ b/google/cloud/storage/tests/curl_sign_blob_integration_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -61,7 +61,7 @@ TEST_F(CurlSignBlobIntegrationTest, Simple) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/error_injection_integration_test.cc b/google/cloud/storage/tests/error_injection_integration_test.cc
index f78ac4a68a8a3..40688acfd8a5d 100644
--- a/google/cloud/storage/tests/error_injection_integration_test.cc
+++ b/google/cloud/storage/tests/error_injection_integration_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::chrono_literals::operator"" _us;
@@ -322,7 +322,7 @@ TEST_F(ErrorInjectionIntegrationTest, InjectSendErrorOnRead) {
 #endif  // _WIN32
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/grpc_integration_test.cc b/google/cloud/storage/tests/grpc_integration_test.cc
index 085c28eda63f5..5d588c7b46b1a 100644
--- a/google/cloud/storage/tests/grpc_integration_test.cc
+++ b/google/cloud/storage/tests/grpc_integration_test.cc
@@ -34,7 +34,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -255,7 +255,7 @@ INSTANTIATE_TEST_SUITE_P(GrpcIntegrationMediaTest, GrpcIntegrationTest,
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/key_file_integration_test.cc b/google/cloud/storage/tests/key_file_integration_test.cc
index 4a883e8124d19..dffe9b4c9fbc9 100644
--- a/google/cloud/storage/tests/key_file_integration_test.cc
+++ b/google/cloud/storage/tests/key_file_integration_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 constexpr auto kJsonEnvVar = "GOOGLE_CLOUD_CPP_STORAGE_TEST_KEY_FILE_JSON";
@@ -150,7 +150,7 @@ INSTANTIATE_TEST_SUITE_P(KeyFileP12Test, KeyFileIntegrationTest,
                          ::testing::Values(kP12EnvVar));
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/minimal_iam_credentials_rest_integration_test.cc b/google/cloud/storage/tests/minimal_iam_credentials_rest_integration_test.cc
index 7371f77a9da51..e1aa6d4696936 100644
--- a/google/cloud/storage/tests/minimal_iam_credentials_rest_integration_test.cc
+++ b/google/cloud/storage/tests/minimal_iam_credentials_rest_integration_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -68,7 +68,7 @@ TEST(MinimalIamCredentialsRestIntegrationTest, GetAccessToken) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_basic_crud_integration_test.cc b/google/cloud/storage/tests/object_basic_crud_integration_test.cc
index 7d78fd4b55916..f5fe23f778bd9 100644
--- a/google/cloud/storage/tests/object_basic_crud_integration_test.cc
+++ b/google/cloud/storage/tests/object_basic_crud_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::ContainsOnce;
@@ -255,7 +255,7 @@ TEST_F(ObjectBasicCRUDIntegrationTest, NonDefaultEndpointWriteXml) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_checksum_integration_test.cc b/google/cloud/storage/tests/object_checksum_integration_test.cc
index cf961c275b539..2a67d6c24c905 100644
--- a/google/cloud/storage/tests/object_checksum_integration_test.cc
+++ b/google/cloud/storage/tests/object_checksum_integration_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -379,7 +379,7 @@ INSTANTIATE_TEST_SUITE_P(ObjectChecksumIntegrationTestXml,
                          ::testing::Values("XML"));
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_compose_many_integration_test.cc b/google/cloud/storage/tests/object_compose_many_integration_test.cc
index aca8f95470b1f..ee312731e36c6 100644
--- a/google/cloud/storage/tests/object_compose_many_integration_test.cc
+++ b/google/cloud/storage/tests/object_compose_many_integration_test.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ObjectComposeManyIntegrationTest =
@@ -69,7 +69,7 @@ TEST_F(ObjectComposeManyIntegrationTest, ComposeMany) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_file_integration_test.cc b/google/cloud/storage/tests/object_file_integration_test.cc
index 520138316bf06..4887c4edd5ca0 100644
--- a/google/cloud/storage/tests/object_file_integration_test.cc
+++ b/google/cloud/storage/tests/object_file_integration_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -656,7 +656,7 @@ TEST_F(ObjectFileIntegrationTest, ResumableUploadFileCustomHeader) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_file_multi_threaded_test.cc b/google/cloud/storage/tests/object_file_multi_threaded_test.cc
index 16a4f798a02b6..aa8937872cb02 100644
--- a/google/cloud/storage/tests/object_file_multi_threaded_test.cc
+++ b/google/cloud/storage/tests/object_file_multi_threaded_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 auto const kObjectSize = 16 * 1024;
@@ -191,7 +191,7 @@ TEST_F(ObjectFileMultiThreadedTest, Download) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_hash_integration_test.cc b/google/cloud/storage/tests/object_hash_integration_test.cc
index f95a831bc625f..514d8d1e9f6db 100644
--- a/google/cloud/storage/tests/object_hash_integration_test.cc
+++ b/google/cloud/storage/tests/object_hash_integration_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -373,7 +373,7 @@ INSTANTIATE_TEST_SUITE_P(ObjectHashIntegrationTestXml,
                          ObjectHashIntegrationTest, ::testing::Values("XML"));
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_insert_integration_test.cc b/google/cloud/storage/tests/object_insert_integration_test.cc
index e4617de1cc14c..cbfa521e3234f 100644
--- a/google/cloud/storage/tests/object_insert_integration_test.cc
+++ b/google/cloud/storage/tests/object_insert_integration_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::CountMatchingEntities;
@@ -676,7 +676,7 @@ INSTANTIATE_TEST_SUITE_P(ObjectInsertWithP12CredentialsTest,
                          ::testing::Values(kP12EnvVar));
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_insert_preconditions_integration_test.cc b/google/cloud/storage/tests/object_insert_preconditions_integration_test.cc
index 70a140828407b..f5ad401fb59bd 100644
--- a/google/cloud/storage/tests/object_insert_preconditions_integration_test.cc
+++ b/google/cloud/storage/tests/object_insert_preconditions_integration_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::GetEnv;
@@ -216,7 +216,7 @@ INSTANTIATE_TEST_SUITE_P(XmlDisabled, ObjectInsertPreconditionsIntegrationTest,
                          ::testing::Values(TestParam{"disable-xml", Fields()}));
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_integration_test.cc b/google/cloud/storage/tests/object_integration_test.cc
index 7d7a94d63a186..9b3aeea5034ac 100644
--- a/google/cloud/storage/tests/object_integration_test.cc
+++ b/google/cloud/storage/tests/object_integration_test.cc
@@ -32,7 +32,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::AclEntityNames;
@@ -872,7 +872,7 @@ TEST_F(ObjectIntegrationTest, WriteWithCustomTime) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_list_objects_versions_integration_test.cc b/google/cloud/storage/tests/object_list_objects_versions_integration_test.cc
index f482b6d237b14..83223e3973b5a 100644
--- a/google/cloud/storage/tests/object_list_objects_versions_integration_test.cc
+++ b/google/cloud/storage/tests/object_list_objects_versions_integration_test.cc
@@ -30,7 +30,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::IsSupersetOf;
@@ -82,7 +82,7 @@ TEST_F(ObjectListObjectsVersionsIntegrationTest, ListObjectsVersions) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_media_integration_test.cc b/google/cloud/storage/tests/object_media_integration_test.cc
index 2179271c9ba14..2e8b598b82e9e 100644
--- a/google/cloud/storage/tests/object_media_integration_test.cc
+++ b/google/cloud/storage/tests/object_media_integration_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -706,7 +706,7 @@ TEST_F(ObjectMediaIntegrationTest, StreamingReadInternalError) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_parallel_upload_integration_test.cc b/google/cloud/storage/tests/object_parallel_upload_integration_test.cc
index 03ade046e1e6f..c3769a0bc6e1a 100644
--- a/google/cloud/storage/tests/object_parallel_upload_integration_test.cc
+++ b/google/cloud/storage/tests/object_parallel_upload_integration_test.cc
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::StatusIs;
@@ -133,7 +133,7 @@ TEST_F(ObjectParallelUploadIntegrationTest, PreconditionsPreventOverwrites) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_plenty_clients_serially_integration_test.cc b/google/cloud/storage/tests/object_plenty_clients_serially_integration_test.cc
index 1cd286a3bb5a4..4d2429cb71ef1 100644
--- a/google/cloud/storage/tests/object_plenty_clients_serially_integration_test.cc
+++ b/google/cloud/storage/tests/object_plenty_clients_serially_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ObjectPlentyClientsSeriallyIntegrationTest =
@@ -96,7 +96,7 @@ TEST_F(ObjectPlentyClientsSeriallyIntegrationTest, PlentyClientsSerially) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_plenty_clients_simultaneously_integration_test.cc b/google/cloud/storage/tests/object_plenty_clients_simultaneously_integration_test.cc
index 6243897521992..b4d0e379faa60 100644
--- a/google/cloud/storage/tests/object_plenty_clients_simultaneously_integration_test.cc
+++ b/google/cloud/storage/tests/object_plenty_clients_simultaneously_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ObjectPlentyClientsSimultaneouslyIntegrationTest =
@@ -94,7 +94,7 @@ TEST_F(ObjectPlentyClientsSimultaneouslyIntegrationTest,
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_read_headers_integration_test.cc b/google/cloud/storage/tests/object_read_headers_integration_test.cc
index df8ad33ee853c..ce82a6174da88 100644
--- a/google/cloud/storage/tests/object_read_headers_integration_test.cc
+++ b/google/cloud/storage/tests/object_read_headers_integration_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::GetEnv;
@@ -89,7 +89,7 @@ TEST_F(ObjectReadHeadersIntegrationTest, SmokeTest) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_read_preconditions_integration_test.cc b/google/cloud/storage/tests/object_read_preconditions_integration_test.cc
index 9e6bed31fa027..610356d50007b 100644
--- a/google/cloud/storage/tests/object_read_preconditions_integration_test.cc
+++ b/google/cloud/storage/tests/object_read_preconditions_integration_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::GetEnv;
@@ -218,7 +218,7 @@ INSTANTIATE_TEST_SUITE_P(XmlEnabled, ObjectReadPreconditionsIntegrationTest,
                          ::testing::Values(TestParam{absl::nullopt}));
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_read_range_integration_test.cc b/google/cloud/storage/tests/object_read_range_integration_test.cc
index 6af5daeba38bf..919ba54ad6ff4 100644
--- a/google/cloud/storage/tests/object_read_range_integration_test.cc
+++ b/google/cloud/storage/tests/object_read_range_integration_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::GetEnv;
@@ -155,7 +155,7 @@ TEST_F(ObjectReadRangeIntegrationTest, ReadLast) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_read_stream_integration_test.cc b/google/cloud/storage/tests/object_read_stream_integration_test.cc
index 28a76e8b05514..4142aeec1cd13 100644
--- a/google/cloud/storage/tests/object_read_stream_integration_test.cc
+++ b/google/cloud/storage/tests/object_read_stream_integration_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class ObjectReadStreamIntegrationTest
@@ -78,7 +78,7 @@ TEST_F(ObjectReadStreamIntegrationTest, MoveWorkingStream) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_resumable_parallel_upload_integration_test.cc b/google/cloud/storage/tests/object_resumable_parallel_upload_integration_test.cc
index e1c49bdc3b671..9c5c64b113165 100644
--- a/google/cloud/storage/tests/object_resumable_parallel_upload_integration_test.cc
+++ b/google/cloud/storage/tests/object_resumable_parallel_upload_integration_test.cc
@@ -31,7 +31,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ObjectResumableParallelUploadIntegrationTest =
@@ -131,7 +131,7 @@ TEST_F(ObjectResumableParallelUploadIntegrationTest, ResumeParallelUploadFile) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_resumable_write_integration_test.cc b/google/cloud/storage/tests/object_resumable_write_integration_test.cc
index 588190a5b203c..dab290543b111 100644
--- a/google/cloud/storage/tests/object_resumable_write_integration_test.cc
+++ b/google/cloud/storage/tests/object_resumable_write_integration_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -391,7 +391,7 @@ TEST_F(ObjectResumableWriteIntegrationTest, WithInvalidXUploadContentLength) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_rewrite_integration_test.cc b/google/cloud/storage/tests/object_rewrite_integration_test.cc
index 3cd7e55e4d673..ce50bf93319b2 100644
--- a/google/cloud/storage/tests/object_rewrite_integration_test.cc
+++ b/google/cloud/storage/tests/object_rewrite_integration_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::storage::testing::CountMatchingEntities;
@@ -424,7 +424,7 @@ TEST_F(ObjectRewriteIntegrationTest, RewriteFailure) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_write_preconditions_integration_test.cc b/google/cloud/storage/tests/object_write_preconditions_integration_test.cc
index 746668c8a7715..ae2d1cf52dfb2 100644
--- a/google/cloud/storage/tests/object_write_preconditions_integration_test.cc
+++ b/google/cloud/storage/tests/object_write_preconditions_integration_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::GetEnv;
@@ -207,7 +207,7 @@ TEST_F(ObjectWritePreconditionsIntegrationTest,
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_write_stream_integration_test.cc b/google/cloud/storage/tests/object_write_stream_integration_test.cc
index 9f1bd71af549b..10dd6c66f27c2 100644
--- a/google/cloud/storage/tests/object_write_stream_integration_test.cc
+++ b/google/cloud/storage/tests/object_write_stream_integration_test.cc
@@ -20,7 +20,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class ObjectWriteStreamIntegrationTest
@@ -99,7 +99,7 @@ TEST_F(ObjectWriteStreamIntegrationTest, DoubleClose) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/object_write_streambuf_integration_test.cc b/google/cloud/storage/tests/object_write_streambuf_integration_test.cc
index 549e0e1e8ed23..651796001db53 100644
--- a/google/cloud/storage/tests/object_write_streambuf_integration_test.cc
+++ b/google/cloud/storage/tests/object_write_streambuf_integration_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 namespace {
 
@@ -89,7 +89,7 @@ TEST_F(ObjectWriteStreambufIntegrationTest, QuantumAndNonQuantum) {
 
 }  // namespace
 }  // namespace internal
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/service_account_integration_test.cc b/google/cloud/storage/tests/service_account_integration_test.cc
index 28fa7c6abd4ec..8df5f53e87da1 100644
--- a/google/cloud/storage/tests/service_account_integration_test.cc
+++ b/google/cloud/storage/tests/service_account_integration_test.cc
@@ -21,7 +21,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::testing_util::IsOk;
@@ -156,7 +156,7 @@ TEST_F(ServiceAccountIntegrationTest, HmacKeyCRUDFailures) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/signed_url_conformance_test.cc b/google/cloud/storage/tests/signed_url_conformance_test.cc
index 24c4c603980f2..42819bdfefab6 100644
--- a/google/cloud/storage/tests/signed_url_conformance_test.cc
+++ b/google/cloud/storage/tests/signed_url_conformance_test.cc
@@ -47,7 +47,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 using ::google::cloud::conformance::storage::v1::PostPolicyV4Test;
 using ::google::cloud::conformance::storage::v1::SigningV4Test;
@@ -277,7 +277,7 @@ INSTANTIATE_TEST_SUITE_P(
     }()));
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/signed_url_integration_test.cc b/google/cloud/storage/tests/signed_url_integration_test.cc
index 1d35695b6eb59..d7fbbca8e1d50 100644
--- a/google/cloud/storage/tests/signed_url_integration_test.cc
+++ b/google/cloud/storage/tests/signed_url_integration_test.cc
@@ -25,7 +25,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class SignedUrlIntegrationTest
@@ -198,7 +198,7 @@ TEST_F(SignedUrlIntegrationTest, CreateV4SignedUrlPut) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/slow_reader_chunk_integration_test.cc b/google/cloud/storage/tests/slow_reader_chunk_integration_test.cc
index c57a369247cf3..6cc0811280282 100644
--- a/google/cloud/storage/tests/slow_reader_chunk_integration_test.cc
+++ b/google/cloud/storage/tests/slow_reader_chunk_integration_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class SlowReaderChunkIntegrationTest
@@ -107,7 +107,7 @@ TEST_F(SlowReaderChunkIntegrationTest, LongPauses) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/slow_reader_stream_integration_test.cc b/google/cloud/storage/tests/slow_reader_stream_integration_test.cc
index 1db699474c3b6..b1184f72d7c91 100644
--- a/google/cloud/storage/tests/slow_reader_stream_integration_test.cc
+++ b/google/cloud/storage/tests/slow_reader_stream_integration_test.cc
@@ -24,7 +24,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class SlowReaderStreamIntegrationTest
@@ -99,7 +99,7 @@ TEST_F(SlowReaderStreamIntegrationTest, LongPauses) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/small_reads_integration_test.cc b/google/cloud/storage/tests/small_reads_integration_test.cc
index 65d035b4416dc..99cbe5631ef59 100644
--- a/google/cloud/storage/tests/small_reads_integration_test.cc
+++ b/google/cloud/storage/tests/small_reads_integration_test.cc
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 class SmallReadsIntegrationTest
@@ -131,7 +131,7 @@ TEST_F(SmallReadsIntegrationTest, ReadFullByChar) {
 }
 
 }  // anonymous namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/thread_integration_test.cc b/google/cloud/storage/tests/thread_integration_test.cc
index f3b60e6e3ef41..5643e0bf86b89 100644
--- a/google/cloud/storage/tests/thread_integration_test.cc
+++ b/google/cloud/storage/tests/thread_integration_test.cc
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 using ObjectNameList = std::vector<std::string>;
 
@@ -229,7 +229,7 @@ TEST_F(ThreadIntegrationTest, ReuseConnections) {
   EXPECT_LT(0U, connected.size());
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/tracing_integration_test.cc b/google/cloud/storage/tests/tracing_integration_test.cc
index d56cc8acc83cc..7301ec3826d73 100644
--- a/google/cloud/storage/tests/tracing_integration_test.cc
+++ b/google/cloud/storage/tests/tracing_integration_test.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::internal::GetEnv;
@@ -80,7 +80,7 @@ TEST_F(TracingIntegrationTest, RawClient) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/tests/unified_credentials_integration_test.cc b/google/cloud/storage/tests/unified_credentials_integration_test.cc
index d9cc3a57d8d31..7dbd9eb36ae91 100644
--- a/google/cloud/storage/tests/unified_credentials_integration_test.cc
+++ b/google/cloud/storage/tests/unified_credentials_integration_test.cc
@@ -27,7 +27,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::google::cloud::MakeAccessTokenCredentials;
@@ -274,7 +274,7 @@ INSTANTIATE_TEST_SUITE_P(UnifiedCredentialsRestIntegrationTest,
                          ::testing::Values("rest"));
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/upload_options.h b/google/cloud/storage/upload_options.h
index 691a378971ea3..b3ad92ad0cb40 100644
--- a/google/cloud/storage/upload_options.h
+++ b/google/cloud/storage/upload_options.h
@@ -23,7 +23,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Request a resumable upload, restoring a previous session if necessary.
  *
@@ -93,7 +93,7 @@ struct UploadLimit
   static char const* name() { return "upload-limit"; }
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/version.cc b/google/cloud/storage/version.cc
index 68bc894a22130..6c344de39a5e6 100644
--- a/google/cloud/storage/version.cc
+++ b/google/cloud/storage/version.cc
@@ -19,7 +19,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::string version_string() { return ::google::cloud::version_string(); }
 
 std::string x_goog_api_client() {
@@ -36,7 +36,7 @@ static_assert(
     "    https://github.com/googleapis/google-cloud-cpp/issues\n"
     "describing your platform details to request support for it.");
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/version.h b/google/cloud/storage/version.h
index d05824a28f264..2cc4ec2d0633e 100644
--- a/google/cloud/storage/version.h
+++ b/google/cloud/storage/version.h
@@ -38,6 +38,9 @@
       " details on GitHub issue #7282.")
 #endif  // _MSC_VER
 
+// This preprocessor symbol is deprecated and should never be used anywhere. It
+// exists solely for backward compatibility to avoid breaking anyone who may
+// have been using it.
 #define STORAGE_CLIENT_NS GOOGLE_CLOUD_CPP_NS
 
 namespace google {
@@ -58,7 +61,7 @@ namespace storage {
  * Note that, consistent with the semver.org guidelines, the v0 version makes
  * no guarantees with respect to backwards compatibility.
  */
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 /**
  * Returns the Google Cloud Storage C++ Client major version.
  *
@@ -89,7 +92,7 @@ std::string version_string();
 /// Returns the value for `x-goog-api-client` header.
 std::string x_goog_api_client();
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/well_known_headers.cc b/google/cloud/storage/well_known_headers.cc
index c2c299e64f98d..45a08f78e7e79 100644
--- a/google/cloud/storage/well_known_headers.cc
+++ b/google/cloud/storage/well_known_headers.cc
@@ -22,7 +22,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::ostream& operator<<(std::ostream& os, CustomHeader const& rhs) {
   if (!rhs.has_value()) {
     return os;
@@ -77,7 +77,7 @@ std::ostream& operator<<(std::ostream& os, SourceEncryptionKey const& rhs) {
   return os << prefix << "*: <not set>";
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/well_known_headers.h b/google/cloud/storage/well_known_headers.h
index 5f9dcadfee88e..7abf3711be02c 100644
--- a/google/cloud/storage/well_known_headers.h
+++ b/google/cloud/storage/well_known_headers.h
@@ -29,7 +29,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Defines well-known request headers using the CRTP.
@@ -280,7 +280,7 @@ EncryptionKeyData CreateKeyFromGenerator(Generator& gen) {
   return EncryptionDataFromBinaryKey(key);
 }
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/well_known_headers_test.cc b/google/cloud/storage/well_known_headers_test.cc
index d8e63f42edb1d..b84a06b47d045 100644
--- a/google/cloud/storage/well_known_headers_test.cc
+++ b/google/cloud/storage/well_known_headers_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 using ::testing::HasSubstr;
@@ -147,7 +147,7 @@ TEST(WellKnownHeader, ValueOrNonEmptyCase) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/well_known_parameters.cc b/google/cloud/storage/well_known_parameters.cc
index cc8a75dd57e4b..b840206854013 100644
--- a/google/cloud/storage/well_known_parameters.cc
+++ b/google/cloud/storage/well_known_parameters.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 std::string PredefinedAcl::HeaderName() const {
   static auto const* const kMapping = new std::map<std::string, std::string>({
       {"authenticatedRead", "authenticated-read"},
@@ -34,7 +34,7 @@ std::string PredefinedAcl::HeaderName() const {
   }
   return loc->second;
 }
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/well_known_parameters.h b/google/cloud/storage/well_known_parameters.h
index b3703d22f46c1..7f13b47fb0a7f 100644
--- a/google/cloud/storage/well_known_parameters.h
+++ b/google/cloud/storage/well_known_parameters.h
@@ -26,7 +26,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace internal {
 /**
  * Defines well-known request headers using the CRTP.
@@ -608,7 +608,7 @@ struct RequestedPolicyVersion
   }
 };
 
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google
diff --git a/google/cloud/storage/well_known_parameters_test.cc b/google/cloud/storage/well_known_parameters_test.cc
index 5cba47ecb9712..851071bfddd82 100644
--- a/google/cloud/storage/well_known_parameters_test.cc
+++ b/google/cloud/storage/well_known_parameters_test.cc
@@ -18,7 +18,7 @@
 namespace google {
 namespace cloud {
 namespace storage {
-inline namespace STORAGE_CLIENT_NS {
+inline namespace GOOGLE_CLOUD_CPP_NS {
 namespace {
 
 TEST(PredefinedAclHeaderNameTest, Simple) {
@@ -46,7 +46,7 @@ TEST(WellKnownParameter, ValueOrNonEmptyCase) {
 }
 
 }  // namespace
-}  // namespace STORAGE_CLIENT_NS
+}  // namespace GOOGLE_CLOUD_CPP_NS
 }  // namespace storage
 }  // namespace cloud
 }  // namespace google