Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/profiles/profile_impl.h

Index: chrome/browser/profiles/profile_impl.h
diff --git a/chrome/browser/profiles/profile_impl.h b/chrome/browser/profiles/profile_impl.h
index 1c6506ad11539e1ff7c5685e6ec88a13100f1883..b3b514cd5dd9f77c21425ac3e4b4985f53963deb 100644
--- a/chrome/browser/profiles/profile_impl.h
+++ b/chrome/browser/profiles/profile_impl.h
@@ -22,6 +22,7 @@
 
 class NetPrefObserver;
 class PrefService;
+class PrefServiceBase;
 class PromoResourceService;
 class SSLConfigServiceManager;
 
@@ -43,7 +44,8 @@ class ExtensionSystem;
 
 // The default profile implementation.
 class ProfileImpl : public Profile,
-                    public content::NotificationObserver {
+                    public content::NotificationObserver,
+                    public PrefObserver {
  public:
   // Value written to prefs when the exit type is EXIT_NORMAL. Public for tests.
   static const char* const kPrefExitTypeNormal;
@@ -126,6 +128,12 @@ class ProfileImpl : public Profile,
                        const content::NotificationSource& source,
                        const content::NotificationDetails& details) OVERRIDE;
 
+  // PrefObserver implementation.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
+
+  // PrefInitObserver implementation.
+
  private:
   friend class Profile;
   FRIEND_TEST_ALL_PREFIXES(StartupBrowserCreatorTest,
@@ -147,6 +155,9 @@ class ProfileImpl : public Profile,
 
   void InitHostZoomMap();
 
+  void OnInitializationCompleted(PrefServiceBase* pref_service,
+                                 bool succeeded);
+
   // Does final prefs initialization and calls Init().
   void OnPrefsLoaded(bool success);