aura: Draw drop shadows under browsers and menus.

ui/aura/desktop_observer.h

 // Copyright (c) 2011 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_DESKTOP_OBSERVER_H_
 #define UI_AURA_DESKTOP_OBSERVER_H_
 #pragma once
 
 #include "ui/aura/aura_export.h"
 
 namespace gfx {
 class Size;
 }
 
 namespace aura {
 
 class Window;
 
 class AURA_EXPORT DesktopObserver {
  public:
   // Invoked after the desktop is resized.
   virtual void OnDesktopResized(const gfx::Size& new_size) {}
 
+  // Invoked when a new window is initialized.
+  virtual void OnWindowInitialized(Window* window) {}
+
   // Invoked when the active window is changed. |active| may be NULL if there is
   // not active window.
   virtual void OnActiveWindowChanged(Window* active) {}
 
  protected:
   virtual ~DesktopObserver() {}
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_DESKTOP_OBSERVER_H_