Remove the singleton instance get/delete methods from RootWindow (yay)

ash/shell.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_SHELL_H_
 #define ASH_SHELL_H_
 #pragma once
 
 #include <utility>
 #include <vector>
@@ skipping 234 matching lines @@
   static Shell* instance_;
 
   // Window mode is computed at shell initialization time, so allow it to be
   // overridden without modifying the global command line.
   static bool compact_window_mode_for_test_;
 
   // If set before the Shell is initialized, the mouse cursor will be hidden
   // when the screen is initially created.
   static bool initially_hide_cursor_;
 
+  scoped_ptr<aura::RootWindow> root_window_;
+
   internal::RootWindowEventFilter* root_filter_;  // not owned
 
   std::vector<WindowAndBoundsPair> to_restore_;
 
 #if !defined(OS_MACOSX)
   scoped_ptr<NestedDispatcherController> nested_dispatcher_controller_;
 
   scoped_ptr<AcceleratorController> accelerator_controller_;
 #endif  // !defined(OS_MACOSX)
 
@@ skipping 57 matching lines @@
   // Offset between the corner of the status area and the corner of the screen
   // when in the compact window mode.
   gfx::Size compact_status_area_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(Shell);
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_H_