Fix virtual/override/final usage in Source/core/{fetch,loader,streams,xmlhttprequest}/.

Source/core/loader/PrerenderHandle.h

 /*
  * Copyright (C) 2013 Google 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 38 matching lines @@
     WTF_MAKE_NONCOPYABLE(PrerenderHandle);
 public:
     static PassOwnPtrWillBeRawPtr<PrerenderHandle> create(Document&, PrerenderClient*, const KURL&, unsigned prerenderRelTypes);
 
     virtual ~PrerenderHandle();
 
     void cancel();
     const KURL& url() const;
 
     // From DocumentLifecycleObserver:
-    virtual void documentWasDetached() override;
+    void documentWasDetached() override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     PrerenderHandle(Document&, PassRefPtr<Prerender>);
 
     void detach();
 
     RefPtr<Prerender> m_prerender;
 };
 
 }
 
 #endif // PrerenderHandle_h