Remove #pragma once from chrome/browser/extensions

chrome/browser/extensions/api/dns/dns_api.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 CHROME_BROWSER_EXTENSIONS_API_DNS_DNS_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_DNS_DNS_API_H_
-#pragma once
 
 #include <string>
 
 #include "chrome/browser/extensions/extension_function.h"
 #include "chrome/browser/io_thread.h"
 #include "net/base/address_list.h"
 #include "net/base/completion_callback.h"
 #include "net/base/host_resolver.h"
 
 class IOThread;
@@ skipping 27 matching lines @@
   // plain pointer to it here as we move from thread to thread.
   IOThread* io_thread_;
 
   scoped_ptr<net::HostResolver::RequestHandle> request_handle_;
   scoped_ptr<net::AddressList> addresses_;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_DNS_DNS_API_H_