Split PrefService into PrefService, PrefServiceSimple and PrefServiceSyncable.

chrome/browser/notifications/notification_prefs_manager.h

Index: chrome/browser/notifications/notification_prefs_manager.h
diff --git a/chrome/browser/notifications/notification_prefs_manager.h b/chrome/browser/notifications/notification_prefs_manager.h
index 922e09f00fb90870b4a34c1a27253751b14d1061..03856aa37b670913179f049bf3ad06f3d1b5bd1e 100644
--- a/chrome/browser/notifications/notification_prefs_manager.h
+++ b/chrome/browser/notifications/notification_prefs_manager.h
@@ -7,7 +7,7 @@
 
 #include "chrome/browser/notifications/balloon_collection.h"
 
-class PrefService;
+class PrefServiceSimple;
 
 // This interface is used to access and mutate the preferences related to
 // desktop notifications.
@@ -16,7 +16,7 @@ class NotificationPrefsManager {
   virtual ~NotificationPrefsManager() {}
 
   // Registers preferences.
-  static void RegisterPrefs(PrefService* prefs);
+  static void RegisterPrefs(PrefServiceSimple* prefs);
 
   // Gets the preference indicating where notifications should be placed.
   virtual BalloonCollection::PositionPreference