Remove #pragma once from ash

ash/wm/power_button_controller.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_POWER_BUTTON_CONTROLLER_H_
 #define ASH_WM_POWER_BUTTON_CONTROLLER_H_
-#pragma once
 
 #include "ash/ash_export.h"
 #include "ash/shell_observer.h"
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time.h"
 #include "base/timer.h"
 #include "ui/aura/root_window_observer.h"
 
 namespace gfx {
@@ skipping 236 matching lines @@
   // |background_layer_|, as the desktop background is now covering the whole
   // screen.
   base::OneShotTimer<PowerButtonController> hide_background_layer_timer_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerButtonController);
 };
 
 }  // namespace ash
 
 #endif  // ASH_WM_POWER_BUTTON_CONTROLLER_H_