Use PrefChangeRegistrar everywhere

chrome/browser/notifications/desktop_notification_service.h

Index: chrome/browser/notifications/desktop_notification_service.h
diff --git a/chrome/browser/notifications/desktop_notification_service.h b/chrome/browser/notifications/desktop_notification_service.h
index d1a4ccccc20ff3cb6e4d32d3d26f1ce8ee84e6dc..2282cd2e682917ddb216486632d1113402c6ac0d 100644
--- a/chrome/browser/notifications/desktop_notification_service.h
+++ b/chrome/browser/notifications/desktop_notification_service.h
@@ -11,6 +11,7 @@
 #include "base/basictypes.h"
 #include "base/string16.h"
 #include "chrome/browser/notifications/notification.h"
+#include "chrome/browser/prefs/pref_change_registrar.h"
 #include "chrome/common/content_settings.h"
 #include "chrome/common/notification_observer.h"
 #include "chrome/common/notification_registrar.h"
@@ -136,6 +137,8 @@ class DesktopNotificationService : public NotificationObserver {
   // UI for desktop toasts.
   NotificationUIManager* ui_manager_;
 
+  PrefChangeRegistrar registrar_;
+
   DISALLOW_COPY_AND_ASSIGN(DesktopNotificationService);
 };