Support storing the VisibilityClient on windows other than the RootWindow. What this means is you c…

ui/aura/client/visibility_client.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_VISIBILITY_CLIENT_H_
 #define UI_AURA_CLIENT_VISIBILITY_CLIENT_H_
 
 #include "ui/aura/aura_export.h"
 
 namespace aura {
-class RootWindow;
 class Window;
 namespace client {
 
 // An interface implemented by an object that manages the visibility of Windows'
 // layers as Window visibility changes.
 class AURA_EXPORT VisibilityClient {
  public:
   // Called when |window|'s visibility is changing to |visible|. The implementor
   // can decide whether or not to pass on the visibility to the underlying
   // layer.
   virtual void UpdateLayerVisibility(Window* window, bool visible) = 0;
 
  protected:
   virtual ~VisibilityClient() {}
 };
 
-// Sets/Gets the VisibilityClient on the RootWindow.
-AURA_EXPORT void SetVisibilityClient(RootWindow* root_window,
-                                     VisibilityClient* client);
-AURA_EXPORT VisibilityClient* GetVisibilityClient(RootWindow* root_window);
+// Sets the VisibilityClient on the Window.
+AURA_EXPORT void SetVisibilityClient(Window* window, VisibilityClient* client);
+
+// Gets the VisibilityClient for the window. This will crawl up |window|'s
+// hierarchy until it finds one.
+AURA_EXPORT VisibilityClient* GetVisibilityClient(Window* window);
 
 }  // namespace clients
 }  // namespace aura
 
 #endif  // UI_AURA_CLIENT_VISIBILITY_CLIENT_H_