Remove content::NotificationObserver dependency from most Prefs code.

chrome/browser/content_settings/content_settings_default_provider.h

Index: chrome/browser/content_settings/content_settings_default_provider.h
diff --git a/chrome/browser/content_settings/content_settings_default_provider.h b/chrome/browser/content_settings/content_settings_default_provider.h
index 2e5d96a1426326803b52577cc94272f85a5af90a..9235293307bf4588c3d91b2aee773b0eb3804da9 100644
--- a/chrome/browser/content_settings/content_settings_default_provider.h
+++ b/chrome/browser/content_settings/content_settings_default_provider.h
@@ -12,10 +12,9 @@
 #include "base/basictypes.h"
 #include "base/memory/linked_ptr.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 "content/public/browser/notification_observer.h"
-#include "content/public/browser/notification_registrar.h"
 
 class PrefService;
 
@@ -25,7 +24,7 @@ namespace content_settings {
 // user prefs. If no default values are set by the user we use the hard coded
 // default values.
 class DefaultProvider : public ObservableProvider,
-                        public content::NotificationObserver {
+                        public PrefObserver {
  public:
   static void RegisterUserPrefs(PrefService* prefs);
 
@@ -51,10 +50,9 @@ class DefaultProvider : 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:
   // Sets the fields of |settings| based on the values in |dictionary|.