Update remaining HTML classes to use OVERRIDE / FINAL when needed

Source/core/html/track/LoadableTextTrack.h

 /*
  * Copyright (C) 2011 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 17 matching lines @@
 
 #include "core/html/track/TextTrack.h"
 #include "core/loader/TextTrackLoader.h"
 #include "wtf/PassRefPtr.h"
 
 namespace WebCore {
 
 class HTMLTrackElement;
 class LoadableTextTrack;
 
-class LoadableTextTrack : public TextTrack, private TextTrackLoaderClient {
+class LoadableTextTrack FINAL : public TextTrack, private TextTrackLoaderClient {
 public:
     static PassRefPtr<LoadableTextTrack> create(HTMLTrackElement* track)
     {
         return adoptRef(new LoadableTextTrack(track));
     }
     virtual ~LoadableTextTrack();
 
     void scheduleLoad(const KURL&);
 
     // This shadows TextTrack::clearClient, but need not be virtual.
@@ skipping 17 matching lines @@
 
     HTMLTrackElement* m_trackElement;
     Timer<LoadableTextTrack> m_loadTimer;
     OwnPtr<TextTrackLoader> m_loader;
     KURL m_url;
     bool m_isDefault;
 };
 } // namespace WebCore
 
 #endif