Adds code for a new Aura shell.

ui/aura_shell/desktop_layout_manager.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_SHELL_DESKTOP_LAYOUT_MANAGER_H_
 #define UI_AURA_SHELL_DESKTOP_LAYOUT_MANAGER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/aura/layout_manager.h"
 
 namespace aura {
 class Window;
 }
 namespace views {
 class Widget;
 }
 
 class DesktopLayoutManager : public aura::LayoutManager {
  public:
   explicit DesktopLayoutManager(aura::Window* owner);
   virtual ~DesktopLayoutManager();
 
   void set_background_widget(views::Widget* background_widget) {
     background_widget_ = background_widget;
   }
 
+  void set_launcher_widget(views::Widget* launcher_widget) {
+    launcher_widget_ = launcher_widget;
+  }
+
  private:
   // Overridden from aura::LayoutManager:
   virtual void OnWindowResized() OVERRIDE;
 
   aura::Window* owner_;
   views::Widget* background_widget_;
+  views::Widget* launcher_widget_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopLayoutManager);
 };
 
 #endif  // UI_AURA_SHELL_DESKTOP_LAYOUT_MANAGER_H_