Enable sync for the settings from the Extension Settings API.

chrome/browser/profiles/profile_impl.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.
 
 // This class gathers state related to a single user profile.
 
 #ifndef CHROME_BROWSER_PROFILES_PROFILE_IMPL_H_
 #define CHROME_BROWSER_PROFILES_PROFILE_IMPL_H_
 #pragma once
 
@@ skipping 180 matching lines @@
   // Keep |prefs_| on top for destruction order because |extension_prefs_|,
   // |net_pref_observer_|, |web_resource_service_|, and |io_data_| store
   // pointers to |prefs_| and shall be destructed first.
   scoped_ptr<PrefService> prefs_;
   scoped_ptr<PrefService> otr_prefs_;
   scoped_ptr<VisitedLinkEventListener> visited_link_event_listener_;
   scoped_ptr<VisitedLinkMaster> visited_link_master_;
   // Keep extension_prefs_ on top of extension_service_ because the latter
   // maintains a pointer to the first and shall be destructed first.
   scoped_ptr<ExtensionPrefs> extension_prefs_;
-  scoped_refptr<ExtensionSettings> extension_settings_;
   scoped_ptr<ExtensionService> extension_service_;
   scoped_refptr<UserScriptMaster> user_script_master_;
   scoped_refptr<ExtensionDevToolsManager> extension_devtools_manager_;
   scoped_ptr<ExtensionProcessManager> extension_process_manager_;
   scoped_refptr<ExtensionMessageService> extension_message_service_;
   scoped_ptr<ExtensionEventRouter> extension_event_router_;
   scoped_ptr<ExtensionNavigationObserver> extension_navigation_observer_;
   scoped_refptr<ExtensionSpecialStoragePolicy>
       extension_special_storage_policy_;
   scoped_ptr<SSLHostState> ssl_host_state_;
@@ skipping 85 matching lines @@
   scoped_ptr<ChromeURLDataManager> chrome_url_data_manager_;
 
   Profile::Delegate* delegate_;
 
   chrome_browser_net::Predictor* predictor_;
 
   DISALLOW_COPY_AND_ASSIGN(ProfileImpl);
 };
 
 #endif  // CHROME_BROWSER_PROFILES_PROFILE_IMPL_H_