Re-land: cc: Use worker context for one-copy tile initialization.

cc/raster/tile_task_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_RASTER_TILE_TASK_WORKER_POOL_H_
 #define CC_RASTER_TILE_TASK_WORKER_POOL_H_
 
 #include "cc/raster/tile_task_runner.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/gfx/geometry/size.h"
@@ skipping 50 matching lines @@
   // already partially complete, and only the subrect needs to be played back.
   static void PlaybackToMemory(void* memory,
                                ResourceFormat format,
                                const gfx::Size& size,
                                size_t stride,
                                const RasterSource* raster_source,
                                const gfx::Rect& canvas_bitmap_rect,
                                const gfx::Rect& canvas_playback_rect,
                                float scale);
 
+  virtual void ReleaseFreeMemory() {}
+
   // Type-checking downcast routine.
   virtual TileTaskRunner* AsTileTaskRunner() = 0;
 };
 
 }  // namespace cc
 
 #endif  // CC_RASTER_TILE_TASK_WORKER_POOL_H_