It is time.

ui/compositor/layer_owner_delegate.h

-// Copyright 2014 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_DELEGATE_H_
-#define UI_COMPOSITOR_LAYER_OWNER_DELEGATE_H_
-
-#include "ui/compositor/compositor_export.h"
-
-namespace ui {
-class Layer;
-
-// Called from RecreateLayer() after the new layer was created. old_layer is
-// the layer that will be returned to the caller of RecreateLayer, new_layer
-// will be the layer now used. Used when the layer has external content
-// (SetTextureMailbox / SetDelegatedFrame was called).
-class COMPOSITOR_EXPORT LayerOwnerDelegate {
- public:
-  virtual void OnLayerRecreated(Layer* old_layer, Layer* new_layer) = 0;
-
- protected:
-  virtual ~LayerOwnerDelegate() {}
-};
-
-}  // namespace ui
-
-#endif  // UI_COMPOSITOR_LAYER_OWNER_DELEGATE_H_