Introduce PrefRegistrySyncable, simplifying PrefServiceSyncable.

chrome/browser/policy/user_policy_signin_service_factory.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_POLICY_USER_POLICY_SIGNIN_SERVICE_FACTORY_H_
 #define CHROME_BROWSER_POLICY_USER_POLICY_SIGNIN_SERVICE_FACTORY_H_
 
 #include "base/memory/singleton.h"
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
-class PrefServiceSyncable;
+class PrefRegistrySyncable;
 
 namespace policy {
 
 class UserPolicySigninService;
 
 // Singleton that owns all UserPolicySigninServices and creates/deletes them as
 // new Profiles are created/shutdown.
 class UserPolicySigninServiceFactory : public ProfileKeyedServiceFactory {
  public:
   // Returns an instance of the UserPolicySigninServiceFactory singleton.
   static UserPolicySigninServiceFactory* GetInstance();
 
   // Returns the instance of UserPolicySigninService for the passed |profile|.
   // Used primarily for testing.
   static UserPolicySigninService* GetForProfile(Profile* profile);
 
  protected:
   // ProfileKeyedServiceFactory implementation.
   virtual ProfileKeyedService* BuildServiceInstanceFor(
       Profile* profile) const OVERRIDE;
 
   // Overridden to cause this object to be created when the profile is created.
   virtual bool ServiceIsCreatedWithProfile() const OVERRIDE;
 
   // Register the preferences related to cloud-based user policy.
-  virtual void RegisterUserPrefs(PrefServiceSyncable* user_prefs) OVERRIDE;
+  virtual void RegisterUserPrefs(PrefRegistrySyncable* registry) OVERRIDE;
 
  private:
   friend struct DefaultSingletonTraits<UserPolicySigninServiceFactory>;
 
   UserPolicySigninServiceFactory();
   virtual ~UserPolicySigninServiceFactory();
 
   DISALLOW_COPY_AND_ASSIGN(UserPolicySigninServiceFactory);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_POLICY_USER_POLICY_SIGNIN_SERVICE_FACTORY_H_