components: Move PrefRegistrySyncable into user_prefs namespace.

chrome/browser/background/background_contents_service_factory.h

Index: chrome/browser/background/background_contents_service_factory.h
diff --git a/chrome/browser/background/background_contents_service_factory.h b/chrome/browser/background/background_contents_service_factory.h
index ecf45f9ea340f1baea71ed420b15ef144aef9a1d..ba4d9b48dd47199114e5ef462991264f1362d3b2 100644
--- a/chrome/browser/background/background_contents_service_factory.h
+++ b/chrome/browser/background/background_contents_service_factory.h
@@ -10,7 +10,6 @@
 #include "chrome/browser/profiles/profile_keyed_service_factory.h"
 
 class BackgroundContentsService;
-class PrefRegistrySyncable;
 class Profile;
 
 // Singleton that owns all BackgroundContentsServices and associates them with
@@ -31,7 +30,8 @@ class BackgroundContentsServiceFactory : public ProfileKeyedServiceFactory {
   // ProfileKeyedServiceFactory:
   virtual ProfileKeyedService* BuildServiceInstanceFor(
       content::BrowserContext* profile) const OVERRIDE;
-  virtual void RegisterUserPrefs(PrefRegistrySyncable* registry) OVERRIDE;
+  virtual void RegisterUserPrefs(
+      user_prefs::PrefRegistrySyncable* registry) OVERRIDE;
   virtual content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const OVERRIDE;
   virtual bool ServiceIsCreatedWithProfile() const OVERRIDE;