Remove #pragma once from ash

ash/shell/content_client/shell_content_browser_client.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_CONTENT_CLIENT_SHELL_CONTENT_BROWSER_CLIENT_H_
 #define ASH_SHELL_CONTENT_CLIENT_SHELL_CONTENT_BROWSER_CLIENT_H_
-#pragma once
 
 #include <string>
 
 #include "base/compiler_specific.h"
 #include "content/public/browser/content_browser_client.h"
 
 namespace content {
 class ShellBrowserContext;
 class ShellBrowserMainParts;
 class ShellResourceDispatcherHostDelegate;
@@ skipping 18 matching lines @@
  private:
   ShellBrowserMainParts* shell_browser_main_parts_;
 
   DISALLOW_COPY_AND_ASSIGN(ShellContentBrowserClient);
 };
 
 }  // namespace shell
 }  // namespace ash
 
 #endif  // ASH_SHELL_CONTENT_CLIENT_SHELL_CONTENT_BROWSER_CLIENT_H_