Remove #pragma once from ash

ash/wm/status_area_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_STATUS_AREA_LAYOUT_MANAGER_H_
 #define ASH_WM_STATUS_AREA_LAYOUT_MANAGER_H_
-#pragma once
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/aura/layout_manager.h"
 
 namespace ash {
 namespace internal {
 
 class ShelfLayoutManager;
 
@@ skipping 26 matching lines @@
 
   ShelfLayoutManager* shelf_;
 
   DISALLOW_COPY_AND_ASSIGN(StatusAreaLayoutManager);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_WM_STATUS_AREA_LAYOUT_MANAGER_H_