It is time.

ui/aura/client/focus_change_observer.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_AURA_CLIENT_FOCUS_CHANGE_OBSERVER_H_
-#define UI_AURA_CLIENT_FOCUS_CHANGE_OBSERVER_H_
-
-#include "ui/aura/aura_export.h"
-
-namespace aura {
-class Window;
-namespace client {
-
-// TODO(beng): this interface will be OBSOLETE by FocusChangeEvent.
-class AURA_EXPORT FocusChangeObserver {
- public:
-  // Called when focus moves from |lost_focus| to |gained_focus|.
-  virtual void OnWindowFocused(Window* gained_focus, Window* lost_focus) = 0;
-
- protected:
-  virtual ~FocusChangeObserver() {}
-};
-
-AURA_EXPORT FocusChangeObserver* GetFocusChangeObserver(Window* window);
-AURA_EXPORT void SetFocusChangeObserver(
-    Window* window,
-    FocusChangeObserver* focus_change_observer);
-
-
-}  // namespace client
-}  // namespace aura
-
-#endif  // UI_AURA_CLIENT_FOCUS_CHANGE_OBSERVER_H_