Support single-threaded impl-side painting

cc/resources/pixel_buffer_raster_worker_pool.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CC_RESOURCES_PIXEL_BUFFER_RASTER_WORKER_POOL_H_
 #define CC_RESOURCES_PIXEL_BUFFER_RASTER_WORKER_POOL_H_
 
 #include <deque>
 #include <vector>
 
@@ skipping 27 matching lines @@
       ResourceProvider* resource_provider,
       size_t max_transfer_buffer_usage_bytes);
 
   // Overridden from RasterWorkerPool:
   Rasterizer* AsRasterizer() override;
 
   // Overridden from Rasterizer:
   void SetClient(RasterizerClient* client) override;
   void Shutdown() override;
   void ScheduleTasks(RasterTaskQueue* queue) override;
+  void WaitForTasksToFinishRunning() override;
   void CheckForCompletedTasks() override;
 
   // Overridden from RasterizerTaskClient:
   scoped_ptr<RasterBuffer> AcquireBufferForRaster(
       const Resource* resource) override;
   void ReleaseBufferForRaster(scoped_ptr<RasterBuffer> buffer) override;
 
  private:
   struct RasterTaskState {
     class TaskComparator {
@@ skipping 73 matching lines @@
 
   base::WeakPtrFactory<PixelBufferRasterWorkerPool>
       raster_finished_weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PixelBufferRasterWorkerPool);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_PIXEL_BUFFER_RASTER_WORKER_POOL_H_