Decouple FileSystem and WebSQL callbacks from VoidCallback and it non-refcounted

Source/modules/notifications/NotificationCenter.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2011, 2012 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 50 matching lines @@
         if (!client()) {
             exceptionState.throwUninformativeAndGenericDOMException(InvalidStateError);
             return 0;
         }
         return WebKitNotification::create(title, body, iconUrl, executionContext(), exceptionState, this);
     }
 
     NotificationClient* client() const { return m_client; }
 
     int checkPermission();
-    void requestPermission(PassRefPtr<VoidCallback> = 0);
+    void requestPermission(PassOwnPtr<VoidCallback> = nullptr);
 
     virtual void stop() OVERRIDE;
 
 private:
     NotificationCenter(ExecutionContext*, NotificationClient*);
 
     class NotificationRequestCallback : public RefCounted<NotificationRequestCallback> {
     public:
-        static PassRefPtr<NotificationRequestCallback> createAndStartTimer(NotificationCenter*, PassRefPtr<VoidCallback>);
+        static PassRefPtr<NotificationRequestCallback> createAndStartTimer(NotificationCenter*, PassOwnPtr<VoidCallback>);
         void startTimer();
         void timerFired(Timer<NotificationRequestCallback>*);
     private:
-        NotificationRequestCallback(NotificationCenter*, PassRefPtr<VoidCallback>);
+        NotificationRequestCallback(NotificationCenter*, PassOwnPtr<VoidCallback>);
 
         RefPtr<NotificationCenter> m_notificationCenter;
         Timer<NotificationRequestCallback> m_timer;
-        RefPtr<VoidCallback> m_callback;
+        OwnPtr<VoidCallback> m_callback;
     };
 
     void requestTimedOut(NotificationRequestCallback*);
 
     NotificationClient* m_client;
     HashSet<RefPtr<NotificationRequestCallback> > m_callbacks;
 };
 
 } // namespace WebCore
 
 #endif // ENABLE(LEGACY_NOTIFICATIONS)
 
 #endif // NotificationCenter_h