| // 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_ENV_OBSERVER_H_ | 
 | #define UI_AURA_ENV_OBSERVER_H_ | 
 |  | 
 | #include "ui/aura/aura_export.h" | 
 |  | 
 | namespace aura { | 
 |  | 
 | class Window; | 
 | class WindowTreeHost; | 
 |  | 
 | class AURA_EXPORT EnvObserver { | 
 |  public: | 
 |   // Called when |window| has been initialized. | 
 |   virtual void OnWindowInitialized(Window* window) = 0; | 
 |  | 
 |  // Called when a WindowTreeHost is initialized. | 
 |   virtual void OnHostInitialized(WindowTreeHost* host) {} | 
 |  | 
 |   // Called when a WindowTreeHost is activated. | 
 |   virtual void OnHostActivated(WindowTreeHost* host) {} | 
 |  | 
 |   // Called right before Env is destroyed. | 
 |   virtual void OnWillDestroyEnv() {} | 
 |  | 
 |  protected: | 
 |   virtual ~EnvObserver() {} | 
 | }; | 
 |  | 
 | }  // namespace aura | 
 |  | 
 | #endif  // UI_AURA_ENV_OBSERVER_H_ |