Introduce PrefRegistrySyncable, simplifying PrefServiceSyncable.

chrome/browser/background/background_contents_service_factory.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.
 
 #ifndef CHROME_BROWSER_BACKGROUND_BACKGROUND_CONTENTS_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_BACKGROUND_BACKGROUND_CONTENTS_SERVICE_FACTORY_H_
 
 #include "base/compiler_specific.h"
 #include "base/memory/singleton.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
 class BackgroundContentsService;
-class PrefServiceSyncable;
+class PrefRegistrySyncable;
 class Profile;
 
 // Singleton that owns all BackgroundContentsServices and associates them with
 // Profiles. Listens for the Profile's destruction notification and cleans up
 // the associated BackgroundContentsService.
 class BackgroundContentsServiceFactory : public ProfileKeyedServiceFactory {
  public:
   static BackgroundContentsService* GetForProfile(Profile* profile);
 
   static BackgroundContentsServiceFactory* GetInstance();
 
  private:
   friend struct DefaultSingletonTraits<BackgroundContentsServiceFactory>;
 
   BackgroundContentsServiceFactory();
   virtual ~BackgroundContentsServiceFactory();
 
   // ProfileKeyedServiceFactory:
   virtual ProfileKeyedService* BuildServiceInstanceFor(
       Profile* profile) const OVERRIDE;
-  virtual void RegisterUserPrefs(PrefServiceSyncable* user_prefs) OVERRIDE;
+  virtual void RegisterUserPrefs(PrefRegistrySyncable* registry) OVERRIDE;
   // Use a separate background contents service for incognito.
   virtual bool ServiceHasOwnInstanceInIncognito() const OVERRIDE;
   virtual bool ServiceIsCreatedWithProfile() const OVERRIDE;
   virtual bool ServiceIsNULLWhileTesting() const OVERRIDE;
 };
 
 #endif  // CHROME_BROWSER_BACKGROUND_BACKGROUND_CONTENTS_SERVICE_FACTORY_H_