Remove #pragma once from chrome/browser/extensions

chrome/browser/extensions/extension_window_list.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_WINDOW_LIST_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_WINDOW_LIST_H_
-#pragma once
 
 #include <list>
 
 #include "base/compiler_specific.h"
 #include "base/memory/singleton.h"
 #include "chrome/browser/extensions/extension_window_controller.h"
 
 class Profile;
 class UIThreadExtensionFunction;
 
@@ skipping 25 matching lines @@
  private:
   friend struct DefaultSingletonTraits<ExtensionWindowList>;
 
   // Entries are not owned by this class and must be removed when destroyed.
   WindowList windows_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionWindowList);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_WINDOW_LIST_H_