Remove #pragma once from chrome/browser/extensions

chrome/browser/extensions/extension_pref_value_map.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_EXTENSION_PREF_VALUE_MAP_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_PREF_VALUE_MAP_H_
-#pragma once
 
 #include <map>
 #include <set>
 #include <string>
 
 #include "base/observer_list.h"
 #include "base/time.h"
 #include "base/values.h"
 #include "chrome/browser/prefs/pref_value_map.h"
 #include "chrome/browser/profiles/profile_keyed_service.h"
@@ skipping 167 matching lines @@
   // being destroyed. In tests, it isn't called, so the notification must
   // be done in the destructor. This bit tracks whether it has been done yet.
   bool destroyed_;
 
   ObserverList<Observer, true> observers_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionPrefValueMap);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_PREF_VALUE_MAP_H_