Remove #pragma once from ash

ash/launcher/app_list_button.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_APP_LIST_BUTTON_H_
 #define ASH_LAUNCHER_APP_LIST_BUTTON_H_
-#pragma once
 
 #include "ui/views/controls/button/image_button.h"
 
 namespace ash {
 namespace internal {
 
 class LauncherButtonHost;
 
 // Button used for the AppList icon on the launcher.
 class AppListButton : public views::ImageButton {
@@ skipping 16 matching lines @@
  private:
   LauncherButtonHost* host_;
 
   DISALLOW_COPY_AND_ASSIGN(AppListButton);
 };
 
 }  // namespace internal
 }  // namespace ash
 
 #endif  // ASH_LAUNCHER_LAUNCHER_BUTTON_H_