Ensure View invalidates Widget::root_layers_ when LayerOwner::RecreateLayer is invoked

ui/compositor/layer_owner.h

 // Copyright (c) 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 UI_COMPOSITOR_LAYER_OWNER_H_
 #define UI_COMPOSITOR_LAYER_OWNER_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/compositor/compositor_export.h"
@@ skipping 15 matching lines @@
   // function, and the caller is then responsible for disposing of the layer
   // once any animation completes. Note that layer() will remain valid until the
   // end of ~LayerOwner().
   scoped_ptr<Layer> AcquireLayer();
 
   // Asks the owner to recreate the layer, returning the old Layer. NULL is
   // returned if there is no existing layer, or recreate is not supported.
   //
   // This does not recurse. Existing children of the layer are moved to the new
   // layer.
-  scoped_ptr<Layer> RecreateLayer();
+  virtual scoped_ptr<Layer> RecreateLayer();
 
   ui::Layer* layer() { return layer_; }
   const ui::Layer* layer() const { return layer_; }
 
   void set_layer_owner_delegate(LayerOwnerDelegate* delegate) {
     layer_owner_delegate_ = delegate;
   }
 
  protected:
   void DestroyLayer();
@@ skipping 10 matching lines @@
   Layer* layer_;
 
   LayerOwnerDelegate* layer_owner_delegate_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerOwner);
 };
 
 }  // namespace ui
 
 #endif  // UI_COMPOSITOR_LAYER_OWNER_H_