Remove #pragma once from ash

ash/wm/shelf_layout_manager.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_WM_SHELF_LAYOUT_MANAGER_H_
 #define ASH_WM_SHELF_LAYOUT_MANAGER_H_
-#pragma once
 
 #include "ash/ash_export.h"
 #include "ash/launcher/launcher.h"
 #include "ash/shell_observer.h"
 #include "ash/wm/shelf_types.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/observer_list.h"
 #include "base/timer.h"
 #include "ui/aura/client/activation_change_observer.h"
@@ skipping 252 matching lines @@
 
   ObserverList<Observer> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ShelfLayoutManager);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_SHELF_LAYOUT_MANAGER_H_