Ban usage of Stopwatch.elapsed() from non-desugared Android code.

While `AndroidJdkLibsChecker` would already issue errors for code like `stopwatch.elapsed().toString()` (since that code includes a call to the banned `Duration.toString()`), it would not issue errors for cases in which callers, e.g., concatenate `stopwatch.elapsed()` into a string or pass `stopwatch.elapsed()` to another method, such as to log it.

The best approach here might be for the checker to automatically inspect all called methods for any reference to banned types in their parameter types or return types. However, that sounds like more implementation work, and it sounds like work that could require depot cleanup. (And maybe there are even reasons you've chosen not to take that approach?) So I figured it would be worth starting with this special case.

PiperOrigin-RevId: 376048914

core/src/main/java/com/google/errorprone/bugpatterns/apidiff/AndroidJdkLibsChecker.java

@@ -82,6 +82,12 @@ private static String packageName(String className) {
     return className.substring(0, className.lastIndexOf('/') + 1);
   }
 
+  private static final ImmutableSetMultimap<String, ClassMemberKey>
+      ADDITIONAL_MEMBERS_REQUIRING_DESUGAR =
+          ImmutableSetMultimap.<String, ClassMemberKey>builder()
+              .put("com/google/common/base/Stopwatch", ClassMemberKey.create("elapsed", ""))
+              .build();
+
   private static class ClassSupportInfo {
 
     private final ImmutableSet<String> allowedPackages;
@@ -95,7 +101,7 @@ private static class ClassSupportInfo {
       allowedClasses = allowJava8 ? DESUGAR_ALLOWED_CLASSES : BASE_ALLOWED_CLASSES;
       bannedClasses = BASE_BANNED_CLASSES;
       allowedMembers = allowJava8 ? DESUGAR_ALLOWED_MEMBERS : ImmutableSetMultimap.of();
-      bannedMembers = allowJava8 ? DESUGAR_BANNED_MEMBERS : ImmutableSetMultimap.of();
+      bannedMembers = allowJava8 ? DESUGAR_BANNED_MEMBERS : ADDITIONAL_MEMBERS_REQUIRING_DESUGAR;
     }
 
     private boolean memberIsAllowed(Map.Entry<String, ClassMemberKey> member) {

core/src/test/java/com/google/errorprone/bugpatterns/apidiff/AndroidJdkLibsCheckerTest.java

@@ -100,6 +100,21 @@ public void typeKind() {
         .doTest();
   }
 
+  @Test
+  public void stopwatchElapsed() {
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            "import com.google.common.base.Stopwatch;",
+            "public class Test {",
+            "  Object o() {",
+            "    // BUG: Diagnostic contains:",
+            "    return Stopwatch.createStarted().elapsed();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
   @Test
   public void allowJava8Flag_packageAllowed() {
     allowJava8Helper