Eliminate Shell::RootWindowList in favor of aura::Window::Windows.

ash/high_contrast/high_contrast_controller.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 ASH_HIGH_CONTRAST_HIGH_CONTRAST_CONTROLLER_H_
 #define ASH_HIGH_CONTRAST_HIGH_CONTRAST_CONTROLLER_H_
 
 #include "ash/ash_export.h"
 #include "base/basictypes.h"
 
 namespace aura {
 class RootWindow;
+class Window;
 }
 
 namespace ash {
 
 class ASH_EXPORT HighContrastController {
  public:
   HighContrastController();
 
   ~HighContrastController() {}
 
   // Set high contrast mode and update all available displays.
   void SetEnabled(bool enabled);
 
   // Update high contrast mode on the just added display.
   void OnRootWindowAdded(aura::RootWindow* root_window);
 
  private:
   // Update high contrast mode on the passed display.
-  void UpdateDisplay(aura::RootWindow* root_window);
+  void UpdateDisplay(aura::Window* root_window);
 
   // Indicates if the high contrast mode is enabled or disabled.
   bool enabled_;
 
   DISALLOW_COPY_AND_ASSIGN(HighContrastController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_HIGH_CONTRAST_HIGH_CONTRAST_CONTROLLER_H_