Re-land: cc: Add raster finished signals to RasterWorkerPool.

cc/resources/pixel_buffer_raster_worker_pool.h

Index: cc/resources/pixel_buffer_raster_worker_pool.h
diff --git a/cc/resources/pixel_buffer_raster_worker_pool.h b/cc/resources/pixel_buffer_raster_worker_pool.h
index be609a832c377906ffde9db88c78f281fff13e5b..7fa692dfd49dd1a0cdb6df8ec691a1f93a4952ed 100644
--- a/cc/resources/pixel_buffer_raster_worker_pool.h
+++ b/cc/resources/pixel_buffer_raster_worker_pool.h
@@ -28,14 +28,13 @@ class CC_EXPORT PixelBufferRasterWorkerPool : public RasterWorkerPool {
 
   // Overridden from RasterWorkerPool:
   virtual void ScheduleTasks(RasterTask::Queue* queue) OVERRIDE;
+  virtual void OnRasterTasksFinished() OVERRIDE;
+  virtual void OnRasterTasksRequiredForActivationFinished() OVERRIDE;
 
  private:
   PixelBufferRasterWorkerPool(ResourceProvider* resource_provider,
                               size_t num_threads);
 
-  // Overridden from RasterWorkerPool:
-  virtual void OnRasterTasksFinished() OVERRIDE;
-
   void FlushUploads();
   void CheckForCompletedUploads();
   void ScheduleCheckForCompletedRasterTasks();
@@ -46,6 +45,9 @@ class CC_EXPORT PixelBufferRasterWorkerPool : public RasterWorkerPool {
       bool was_canceled,
       bool needs_upload);
   void DidCompleteRasterTask(internal::RasterWorkerPoolTask* task);
+  unsigned NumPendingRasterTasks() const;
+  void CheckIfFinishedRunningTasks();
+  void CheckIfFinishedRunningTasksRequiredForActivation();
 
   bool shutdown_;
 
@@ -55,11 +57,17 @@ class CC_EXPORT PixelBufferRasterWorkerPool : public RasterWorkerPool {
   TaskDeque tasks_with_pending_upload_;
   TaskDeque completed_tasks_;
 
+  typedef std::set<internal::RasterWorkerPoolTask*> TaskSet;
+  TaskSet tasks_required_for_activation_;
+
   size_t bytes_pending_upload_;
   bool has_performed_uploads_since_last_flush_;
   base::CancelableClosure check_for_completed_raster_tasks_callback_;
   bool check_for_completed_raster_tasks_pending_;
 
+  bool finished_running_tasks_pending_;
+  bool finished_running_tasks_required_for_activation_pending_;
+
   DISALLOW_COPY_AND_ASSIGN(PixelBufferRasterWorkerPool);
 };