Changes launcher so that when animating hidden the background doesn't

ash/wm/shelf_layout_manager.h

Index: ash/wm/shelf_layout_manager.h
diff --git a/ash/wm/shelf_layout_manager.h b/ash/wm/shelf_layout_manager.h
index 0bd7c75cebf5d3b14189b296c0fe8c7d0e3992b7..d8a38bcb83040272fa4a1b08a55793b4defeade1 100644
--- a/ash/wm/shelf_layout_manager.h
+++ b/ash/wm/shelf_layout_manager.h
@@ -173,6 +173,7 @@ class ASH_EXPORT ShelfLayoutManager :
 
  private:
   class AutoHideEventFilter;
+  class UpdateShelfObserver;
   friend class ash::ScreenAsh;
   friend class ShelfLayoutManagerTest;
   FRIEND_TEST_ALL_PREFIXES(ShelfLayoutManagerTest, SetAutoHideBehavior);
@@ -306,6 +307,9 @@ class ASH_EXPORT ShelfLayoutManager :
   // Manage the auto-hide state during the gesture.
   AutoHideState gesture_drag_auto_hide_state_;
 
+  // Used to delay updating shelf background.
+  UpdateShelfObserver* update_shelf_observer_;
+
   DISALLOW_COPY_AND_ASSIGN(ShelfLayoutManager);
 };