Remove #pragma once from ash

ash/shell/example_factory.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_SHELL_EXAMPLE_FACTORY_H_
 #define ASH_SHELL_EXAMPLE_FACTORY_H_
-#pragma once
 
 namespace app_list {
 class AppListViewDelegate;
 }
 
 namespace views {
 class View;
 }
 
 namespace ash {
 namespace shell {
 
 void CreatePointyBubble(views::View* anchor_view);
 
 void CreateLockScreen();
 
 // Creates a window showing samples of commonly used widgets.
 void CreateWidgetsWindow();
 
 app_list::AppListViewDelegate* CreateAppListViewDelegate();
 
 }  // namespace shell
 }  // namespace ash
 
 #endif  // ASH_SHELL_EXAMPLE_FACTORY_H_