cc: Ensure members needed on task completion get called on valid thread.

cc/tiles/tile_manager.h

Index: cc/tiles/tile_manager.h
diff --git a/cc/tiles/tile_manager.h b/cc/tiles/tile_manager.h
index b522423415fd50d29a53ec3c5adb95b15f2a11b6..7c45c8f1786e4cce9f43bad2717b2e25e3ddc209 100644
--- a/cc/tiles/tile_manager.h
+++ b/cc/tiles/tile_manager.h
@@ -197,10 +197,10 @@ class CC_EXPORT TileManager {
     return has_scheduled_tile_tasks_;
   }
 
-  void OnRasterTaskCompleted(std::unique_ptr<RasterBuffer> raster_buffer,
-                             Tile* tile,
-                             Resource* resource,
-                             bool was_canceled);
+  static void OnRasterTaskCompleted(
+      std::unique_ptr<RasterBuffer> raster_buffer,
+      TileTask::TaskCompletionInfo* completion_info,
+      bool was_canceled);
 
  protected:
   TileManager(TileManagerClient* client,