Move Extension into extensions namespace

chrome/browser/extensions/component_loader.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_COMPONENT_LOADER_H_
 #define CHROME_BROWSER_EXTENSIONS_COMPONENT_LOADER_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/file_path.h"
 #include "base/gtest_prod_util.h"
 #include "base/values.h"
 #include "chrome/browser/prefs/pref_change_registrar.h"
 #include "content/public/browser/notification_observer.h"
 
-class Extension;
 class ExtensionServiceInterface;
 class PrefService;
 
 namespace extensions {
 
+class Extension;
+
 // For registering, loading, and unloading component extensions.
 class ComponentLoader : public content::NotificationObserver {
  public:
   ComponentLoader(ExtensionServiceInterface* extension_service,
                   PrefService* prefs,
                   PrefService* local_state);
   virtual ~ComponentLoader();
 
   size_t registered_extensions_count() const {
     return component_extensions_.size();
@@ skipping 91 matching lines @@
   RegisteredComponentExtensions component_extensions_;
 
   PrefChangeRegistrar pref_change_registrar_;
 
   DISALLOW_COPY_AND_ASSIGN(ComponentLoader);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_COMPONENT_LOADER_H_