Remove #pragma once from ash

ash/system/power/tray_power.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_SYSTEM_POWER_TRAY_POWER_H_
 #define ASH_SYSTEM_POWER_TRAY_POWER_H_
-#pragma once
 
 #include "ash/system/power/power_status_observer.h"
 #include "ash/system/tray/system_tray_item.h"
 
 class SkBitmap;
 
 namespace gfx {
 class ImageSkia;
 }
 
@@ skipping 46 matching lines @@
   tray::PowerNotificationView* notification_view_;
   NotificationState notification_state_;
 
   DISALLOW_COPY_AND_ASSIGN(TrayPower);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_SYSTEM_POWER_TRAY_POWER_H_