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

cc/resources/image_raster_worker_pool.h

Index: cc/resources/image_raster_worker_pool.h
diff --git a/cc/resources/image_raster_worker_pool.h b/cc/resources/image_raster_worker_pool.h
index 453b3a39970ebc846af53baa73692d5f2a484680..1dca0dedf6e2cbbffced283c45eca8b74a605ee2 100644
--- a/cc/resources/image_raster_worker_pool.h
+++ b/cc/resources/image_raster_worker_pool.h
@@ -19,6 +19,9 @@ class CC_EXPORT ImageRasterWorkerPool : public RasterWorkerPool {
         new ImageRasterWorkerPool(resource_provider, num_threads));
   }
 
+  // Overridden from WorkerPool:
+  virtual void Shutdown() OVERRIDE;
+
   // Overridden from RasterWorkerPool:
   virtual void ScheduleTasks(RasterTask::Queue* queue) OVERRIDE;
 
@@ -26,11 +29,22 @@ class CC_EXPORT ImageRasterWorkerPool : public RasterWorkerPool {
   ImageRasterWorkerPool(ResourceProvider* resource_provider,
                         size_t num_threads);
 
+  void OnRasterFinished(int64 schedule_raster_tasks_count);
+  void OnRasterRequiredForActivationFinished(
+      int64 schedule_raster_tasks_count);
+
   void OnRasterTaskCompleted(
       scoped_refptr<internal::RasterWorkerPoolTask> task, bool was_canceled);
 
   TaskMap image_tasks_;
 
+  base::WeakPtrFactory<ImageRasterWorkerPool> weak_ptr_factory_;
+  int64 schedule_raster_tasks_count_;
+
+  scoped_refptr<internal::WorkerPoolTask> raster_finished_task_;
+  scoped_refptr<internal::WorkerPoolTask>
+      raster_required_for_activation_finished_task_;
+
   DISALLOW_COPY_AND_ASSIGN(ImageRasterWorkerPool);
 };