Fix virtual/override/final usage in Source/core/dom/.

Source/core/dom/Fullscreen.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
@@ skipping 66 matching lines @@
 
     void setFullScreenLayoutObject(LayoutFullScreen*);
     LayoutFullScreen* fullScreenLayoutObject() const { return m_fullScreenLayoutObject; }
     void fullScreenLayoutObjectDestroyed();
 
     void elementRemoved(Element&);
 
     // Mozilla API
     Element* webkitCurrentFullScreenElement() const { return m_fullScreenElement.get(); }
 
-    virtual void documentWasDetached() override;
+    void documentWasDetached() override;
 #if !ENABLE(OILPAN)
-    virtual void documentWasDisposed() override;
+    void documentWasDisposed() override;
 #endif
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     static Fullscreen* fromIfExistsSlow(Document&);
 
     explicit Fullscreen(Document&);
 
     Document* document();
@@ skipping 26 matching lines @@
 inline Fullscreen* Fullscreen::fromIfExists(Document& document)
 {
     if (!document.hasFullscreenSupplement())
         return 0;
     return fromIfExistsSlow(document);
 }
 
 } // namespace blink
 
 #endif // Fullscreen_h