adding render stats for deferred image decoding

cc/tile_manager.h

Index: cc/tile_manager.h
diff --git a/cc/tile_manager.h b/cc/tile_manager.h
index d80e2f1a0b1860441c47e99a947c139821a788a8..cc140c4991a429af965204b5d563786c089104ea 100644
--- a/cc/tile_manager.h
+++ b/cc/tile_manager.h
@@ -104,9 +104,12 @@ class CC_EXPORT TileManager {
       RenderingStats*);
   void DidFinishTileInitialization(Tile*);
   void DispatchImageDecodingTasksForTile(Tile*);
-  void OnImageDecodingTaskCompleted(scoped_refptr<Tile>, uint32_t);
+  void OnImageDecodingTaskCompleted(scoped_refptr<Tile>,
+                                    uint32_t,
+                                    RenderingStats*);
   void DispatchOneImageDecodingTask(
       RasterThread*, scoped_refptr<Tile>, skia::LazyPixelRef*);
+  void GatherPixelRefsForFile(Tile*);
   RasterThread* GetFreeRasterThread();
 
   TileManagerClient* client_;