cc: Remove layers that are not drawn from tile manager.

cc/resources/tile_manager.h

 // Copyright 2012 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_TILE_MANAGER_H_
 #define CC_RESOURCES_TILE_MANAGER_H_
 
 #include <deque>
 #include <queue>
 #include <set>
@@ skipping 270 matching lines @@
   }
 
   void FreeResourceForTile(Tile* tile, RasterMode mode);
   void FreeResourcesForTile(Tile* tile);
   void FreeUnusedResourcesForTile(Tile* tile);
   scoped_refptr<ImageDecodeTask> CreateImageDecodeTask(Tile* tile,
                                                        SkPixelRef* pixel_ref);
   scoped_refptr<RasterTask> CreateRasterTask(Tile* tile);
   scoped_ptr<base::Value> GetMemoryRequirementsAsValue() const;
   void UpdatePrioritizedTileSetIfNeeded();
+  void CleanUpLayers();
 
   TileManagerClient* client_;
   ResourcePool* resource_pool_;
   scoped_ptr<RasterizerDelegate> rasterizer_delegate_;
   GlobalStateThatImpactsTilePriority global_state_;
 
   typedef base::hash_map<Tile::Id, Tile*> TileMap;
   TileMap tiles_;
 
   PrioritizedTileSet prioritized_tiles_;
@@ skipping 39 matching lines @@
   std::vector<scoped_refptr<RasterTask> > orphan_raster_tasks_;
 
   std::vector<PictureLayerImpl*> layers_;
 
   DISALLOW_COPY_AND_ASSIGN(TileManager);
 };
 
 }  // namespace cc
 
 #endif  // CC_RESOURCES_TILE_MANAGER_H_