Take extensions out of Profile into a profile-keyed service, ExtensionSystem.

chrome/browser/extensions/extension_service.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_SERVICE_H_
 #define CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_
 #pragma once
 
 #include <list>
 #include <map>
@@ skipping 40 matching lines @@
 class CrxInstaller;
 class ExtensionBrowserEventRouter;
 class ExtensionContentSettingsStore;
 class ExtensionCookiesEventRouter;
 class ExtensionDownloadsEventRouter;
 class ExtensionFileBrowserEventRouter;
 class ExtensionGlobalError;
 class ExtensionManagementEventRouter;
 class ExtensionPreferenceEventRouter;
 class ExtensionSyncData;
+class ExtensionSystem;
 class ExtensionToolbarModel;
 class ExtensionUpdater;
 class ExtensionWebNavigationEventRouter;
 class HistoryExtensionEventRouter;
 class GURL;
 class PendingExtensionManager;
 class Profile;
 class SyncData;
 class Version;
 
@@ skipping 626 matching lines @@
   // Call UpdatePluginListWithNaClModules() after registering or unregistering
   // a NaCl module to see those changes reflected in the PluginList.
   void UpdatePluginListWithNaClModules();
 
   // Start the process of installing an application shortcut.
   // The process is finished when OnImageLoaded is called.
   void StartInstallApplicationShortcut(const Extension* extension);
 
   NaClModuleInfoList::iterator FindNaClModule(const GURL& url);
 
-  // The profile this ExtensionService is part of.
+  // The normal profile associated with this ExtensionService.
   Profile* profile_;
 
+  // The ExtensionSystem for the profile above.
+  ExtensionSystem* system_;
+
   // Preferences for the owning profile (weak reference).
   ExtensionPrefs* extension_prefs_;
 
   // Settings for the owning profile.
   scoped_ptr<extensions::SettingsFrontend> settings_frontend_;
 
   // The current list of installed extensions.
   // TODO(aa): This should use chrome/common/extensions/extension_set.h.
   ExtensionSet extensions_;
 
@@ skipping 128 matching lines @@
   scoped_ptr<ExtensionGlobalError> extension_global_error_;
 
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            InstallAppsWithUnlimtedStorage);
   FRIEND_TEST_ALL_PREFIXES(ExtensionServiceTest,
                            InstallAppsAndCheckStorageProtection);
   DISALLOW_COPY_AND_ASSIGN(ExtensionService);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_SERVICE_H_