Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/content_settings/content_settings_pref_provider.h

Index: chrome/browser/content_settings/content_settings_pref_provider.h
diff --git a/chrome/browser/content_settings/content_settings_pref_provider.h b/chrome/browser/content_settings/content_settings_pref_provider.h
index 9595de76a4b3db64ee5fd7903954a3a95d3ceccc..1efc5ccbf446eb16581f2c768589cfe0e5ba25d3 100644
--- a/chrome/browser/content_settings/content_settings_pref_provider.h
+++ b/chrome/browser/content_settings/content_settings_pref_provider.h
@@ -11,12 +11,11 @@
 
 #include "base/basictypes.h"
 #include "base/prefs/public/pref_change_registrar.h"
+#include "base/prefs/public/pref_observer.h"
 #include "base/synchronization/lock.h"
 #include "chrome/browser/content_settings/content_settings_observable_provider.h"
 #include "chrome/browser/content_settings/content_settings_origin_identifier_value_map.h"
 #include "chrome/browser/content_settings/content_settings_utils.h"
-#include "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 
 class PrefService;
 
@@ -29,7 +28,7 @@ namespace content_settings {
 // Content settings provider that provides content settings from the user
 // preference.
 class PrefProvider : public ObservableProvider,
-                     public content::NotificationObserver {
+                     public PrefObserver {
  public:
   static void RegisterUserPrefs(PrefService* prefs);
 
@@ -55,10 +54,9 @@ class PrefProvider : public ObservableProvider,
 
   virtual void ShutdownOnUIThread() OVERRIDE;
 
-  // content::NotificationObserver implementation.
-  virtual void Observe(int type,
-                       const content::NotificationSource& source,
-                       const content::NotificationDetails& details) OVERRIDE;
+  // PrefObserver implementation.
+  virtual void OnPreferenceChanged(PrefServiceBase* service,
+                                   const std::string& pref_name) OVERRIDE;
 
  private:
   friend class DeadlockCheckerThread;  // For testing.