Remove #pragma once from chrome/browser/extensions

chrome/browser/extensions/extension_tab_id_map.h

 // Copyright (c) 2011 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_EXTENSION_TAB_ID_MAP_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_TAB_ID_MAP_H_
-#pragma once
 
 #include <map>
 #include <utility>
 
 #include "base/basictypes.h"
 #include "base/memory/singleton.h"
 
 // This class keeps track of a map between renderer IDs and tab/window IDs, for
 // use on the IO thread. All methods should be called on the IO thread except
 // for Init and Shutdown.
@@ skipping 29 matching lines @@
   void ClearTabAndWindowId(
       int render_process_host_id, int routing_id);
 
   TabObserver* observer_;
   TabAndWindowIdMap map_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionTabIdMap);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_TAB_ID_MAP_H_