Make Chrome limp briefly before freaking out with aura no ash.

ui/aura/desktop/desktop_stacking_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_DESKTOP_DESKTOP_STACKING_CLIENT_H_
 #define UI_AURA_DESKTOP_DESKTOP_STACKING_CLIENT_H_
 
 #include "ui/aura/client/stacking_client.h"
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
 #include "ui/aura/aura_export.h"
 
 namespace aura {
+class RootWindow;
 class Window;
 
 // A stacking client for the desktop; always sets the default parent to the
 // RootWindow of the passed in Window.
 class AURA_EXPORT DesktopStackingClient : public client::StackingClient {
  public:
   DesktopStackingClient();
   virtual ~DesktopStackingClient();
 
   // Overridden from client::StackingClient:
   virtual Window* GetDefaultParent(Window* window) OVERRIDE;
 
+ private:
+  // Windows with NULL parents are parented to this.
+  scoped_ptr<aura::RootWindow> null_parent_;
+
   DISALLOW_COPY_AND_ASSIGN(DesktopStackingClient);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_DESKTOP_DESKTOP_STACKING_CLIENT_H_