Split PrefService into PrefService, PrefServiceSimple and PrefServiceSyncable.

chrome/browser/net/net_pref_observer.h

Index: chrome/browser/net/net_pref_observer.h
diff --git a/chrome/browser/net/net_pref_observer.h b/chrome/browser/net/net_pref_observer.h
index f7dab1d99eb07a80dc9915fb74336bf35a0436ce..7409ad3b8eeceb469f0fe59ba9cfc1d08df525ea 100644
--- a/chrome/browser/net/net_pref_observer.h
+++ b/chrome/browser/net/net_pref_observer.h
@@ -17,6 +17,7 @@ class PrerenderManager;
 }
 
 class PrefService;
+class PrefServiceSyncable;
 
 // Monitors network-related preferences for changes and applies them.
 // The supplied PrefService must outlive this NetPrefObserver.
@@ -31,7 +32,7 @@ class NetPrefObserver {
                   chrome_browser_net::Predictor* predictor);
   virtual ~NetPrefObserver();
 
-  static void RegisterPrefs(PrefService* prefs);
+  static void RegisterPrefs(PrefServiceSyncable* prefs);
 
  private:
   void ApplySettings();