Better Z-index support.

ui/aura/root_window.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_ROOT_WINDOW_H_
 #define UI_AURA_ROOT_WINDOW_H_
 #pragma once
 
 #include "ui/aura/window.h"
 
 namespace aura {
 namespace internal {
 
 class FocusManager;
 
 // A Window subclass that handles event targeting for certain types of
 // MouseEvent.
 class RootWindow : public Window {
  public:
   RootWindow();
   virtual ~RootWindow();
 
   // Handles a mouse event. Returns true if handled.
   bool HandleMouseEvent(const MouseEvent& event);
 
   // Handles a key event. Returns true if handled.
   bool HandleKeyEvent(const KeyEvent& event);
 
   // Overridden from Window:
-  virtual bool IsTopLevelWindowContainer() const OVERRIDE;
   virtual FocusManager* GetFocusManager() OVERRIDE;
 
  private:
   Window* mouse_pressed_handler_;
   scoped_ptr<FocusManager> focus_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(RootWindow);
 };
 
 }  // namespace internal
 }  // namespace aura
 
 #endif  // UI_AURA_ROOT_WINDOW_H_