Remove #pragma once from ash

ash/launcher/launcher_button_host.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_LAUNCHER_LAUNCHER_BUTTON_HOST_H_
 #define ASH_LAUNCHER_LAUNCHER_BUTTON_HOST_H_
-#pragma once
 
 #include "ash/ash_export.h"
 #include "ash/wm/shelf_types.h"
 #include "base/string16.h"
 
 namespace views {
 class MouseEvent;
 class View;
 }
 
@@ skipping 31 matching lines @@
   virtual string16 GetAccessibleName(const views::View* view) = 0;
 
  protected:
   virtual ~LauncherButtonHost() {}
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_LAUNCHER_LAUNCHER_BUTTON_HOST_H_