deps: patch the V8 API to be backwards compatible with 6.7

PR-URL: #21668
Fixes: https://github.com/I
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Myles Borins <myles.borins@gmail.com>

deps/v8/include/libplatform/libplatform.h

@@ -62,7 +62,7 @@ V8_PLATFORM_EXPORT bool PumpMessageLoop(
     v8::Platform* platform, v8::Isolate* isolate,
     MessageLoopBehavior behavior = MessageLoopBehavior::kDoNotWait);
 
-V8_PLATFORM_EXPORT V8_DEPRECATED(
+V8_PLATFORM_EXPORT V8_DEPRECATE_SOON(
     "This function has become obsolete and is essentially a nop",
     void EnsureEventLoopInitialized(v8::Platform* platform,
                                     v8::Isolate* isolate));

deps/v8/include/v8-inspector.h

@@ -99,7 +99,6 @@ class V8_EXPORT V8ContextInfo {
 
 class V8_EXPORT V8StackTrace {
  public:
-  virtual StringView firstNonEmptySourceURL() const = 0;
   virtual bool isEmpty() const = 0;
   virtual StringView topSourceURL() const = 0;
   virtual int topLineNumber() const = 0;

deps/v8/include/v8-platform.h

@@ -246,6 +246,16 @@ class PageAllocator {
  */
 class Platform {
  public:
+  /**
+   * This enum is used to indicate whether a task is potentially long running,
+   * or causes a long wait. The embedder might want to use this hint to decide
+   * whether to execute the task on a dedicated thread.
+   */
+  enum ExpectedRuntime {
+    kShortRunningTask,
+    kLongRunningTask
+  };
+
   virtual ~Platform() = default;
 
   /**
@@ -280,25 +290,101 @@ class Platform {
   virtual bool OnCriticalMemoryPressure(size_t length) { return false; }
 
   /**
-   * Gets the number of worker threads used by
-   * Call(BlockingTask)OnWorkerThread(). This can be used to estimate the number
-   * of tasks a work package should be split into. A return value of 0 means
-   * that there are no worker threads available. Note that a value of 0 won't
-   * prohibit V8 from posting tasks using |CallOnWorkerThread|.
+   * Gets the number of worker threads used by GetWorkerThreadsTaskRunner() and
+   * CallOnWorkerThread(). This can be used to estimate the number of tasks a
+   * work package should be split into. A return value of 0 means that there are
+   * no worker threads available. Note that a value of 0 won't prohibit V8 from
+   * posting tasks using |CallOnWorkerThread|.
+   */
+  virtual int NumberOfWorkerThreads() {
+    return static_cast<int>(NumberOfAvailableBackgroundThreads());
+  }
+
+  /**
+   * Deprecated. Use NumberOfWorkerThreads() instead.
+   * TODO(gab): Remove this when all embedders override
+   * NumberOfWorkerThreads() instead.
    */
-  virtual int NumberOfWorkerThreads() = 0;
+  V8_DEPRECATE_SOON(
+      "NumberOfAvailableBackgroundThreads() is deprecated, use "
+      "NumberOfAvailableBackgroundThreads() instead.",
+      virtual size_t NumberOfAvailableBackgroundThreads()) {
+    return 0;
+  }
 
   /**
    * Returns a TaskRunner which can be used to post a task on the foreground.
    * This function should only be called from a foreground thread.
    */
   virtual std::shared_ptr<v8::TaskRunner> GetForegroundTaskRunner(
-      Isolate* isolate) = 0;
+      Isolate* isolate) {
+    // TODO(ahaas): Make this function abstract after it got implemented on all
+    // platforms.
+    return {};
+  }
+
+  /**
+   * Returns a TaskRunner which can be used to post a task on a background.
+   * This function should only be called from a foreground thread.
+   */
+  V8_DEPRECATE_SOON(
+      "GetBackgroundTaskRunner() is deprecated, use "
+      "GetWorkerThreadsTaskRunner() "
+      "instead.",
+      virtual std::shared_ptr<v8::TaskRunner> GetBackgroundTaskRunner(
+          Isolate* isolate)) {
+    // TODO(gab): Remove this method when all embedders have moved to
+    // GetWorkerThreadsTaskRunner().
+
+    // An implementation needs to be provided here because this is called by the
+    // default GetWorkerThreadsTaskRunner() implementation below. In practice
+    // however, all code either:
+    //  - Overrides GetWorkerThreadsTaskRunner() (thus not making this call) --
+    //    i.e. all v8 code.
+    //  - Overrides this method (thus not making this call) -- i.e. all
+    //    unadapted embedders.
+    abort();
+  }
+
+  /**
+   * Returns a TaskRunner which can be used to post async tasks on a worker.
+   * This function should only be called from a foreground thread.
+   */
+  virtual std::shared_ptr<v8::TaskRunner> GetWorkerThreadsTaskRunner(
+      Isolate* isolate) {
+    // TODO(gab): Make this function abstract after it got implemented on all
+    // platforms.
+    return GetBackgroundTaskRunner(isolate);
+  }
+
+  /**
+   * Schedules a task to be invoked on a background thread. |expected_runtime|
+   * indicates that the task will run a long time. The Platform implementation
+   * takes ownership of |task|. There is no guarantee about order of execution
+   * of tasks wrt order of scheduling, nor is there a guarantee about the
+   * thread the task will be run on.
+   */
+  V8_DEPRECATE_SOON(
+      "ExpectedRuntime is deprecated, use CallOnWorkerThread() instead.",
+      virtual void CallOnBackgroundThread(Task* task,
+                                          ExpectedRuntime expected_runtime)) {
+    // An implementation needs to be provided here because this is called by the
+    // default implementation below. In practice however, all code either:
+    //  - Overrides the new method (thus not making this call) -- i.e. all v8
+    //    code.
+    //  - Overrides this method (thus not making this call) -- i.e. all
+    //    unadapted embedders.
+    abort();
+  }
 
   /**
    * Schedules a task to be invoked on a worker thread.
+   * TODO(gab): Make pure virtual when all embedders override this instead of
+   * CallOnBackgroundThread().
    */
-  virtual void CallOnWorkerThread(std::unique_ptr<Task> task) = 0;
+  virtual void CallOnWorkerThread(std::unique_ptr<Task> task) {
+    CallOnBackgroundThread(task.release(), kShortRunningTask);
+  }
 
   /**
    * Schedules a task that blocks the main thread to be invoked with
@@ -310,13 +396,6 @@ class Platform {
     CallOnWorkerThread(std::move(task));
   }
 
-  /**
-   * Schedules a task to be invoked on a worker thread after |delay_in_seconds|
-   * expires.
-   */
-  virtual void CallDelayedOnWorkerThread(std::unique_ptr<Task> task,
-                                         double delay_in_seconds) = 0;
-
   /**
    * Schedules a task to be invoked on a foreground thread wrt a specific
    * |isolate|. Tasks posted for the same isolate should be execute in order of
@@ -342,14 +421,14 @@ class Platform {
    * The definition of "foreground" is opaque to V8.
    */
   virtual void CallIdleOnForegroundThread(Isolate* isolate, IdleTask* task) {
-    // This must be overriden if |IdleTasksEnabled()|.
-    abort();
+    // TODO(ulan): Make this function abstract after V8 roll in Chromium.
   }
 
   /**
    * Returns true if idle tasks are enabled for the given |isolate|.
    */
   virtual bool IdleTasksEnabled(Isolate* isolate) {
+    // TODO(ulan): Make this function abstract after V8 roll in Chromium.
     return false;
   }
 

deps/v8/include/v8-profiler.h

@@ -54,11 +54,7 @@ namespace v8 {
  */
 class V8_EXPORT TracingCpuProfiler {
  public:
-  V8_DEPRECATE_SOON(
-      "The profiler is created automatically with the isolate.\n"
-      "No need to create it explicitly.",
-      static std::unique_ptr<TracingCpuProfiler> Create(Isolate*));
-
+  static std::unique_ptr<TracingCpuProfiler> Create(Isolate*);
   virtual ~TracingCpuProfiler() = default;
 
  protected: