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

Source/core/html/track/TrackEvent.h

 /*
  * Copyright (C) 2011 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:
  * 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 19 matching lines @@
 #include "core/html/track/TrackBase.h"
 #include "core/html/track/TrackEventInit.h"
 
 namespace blink {
 
 class VideoTrackOrAudioTrackOrTextTrack;
 
 class TrackEvent final : public Event {
     DEFINE_WRAPPERTYPEINFO();
 public:
-    virtual ~TrackEvent();
+    ~TrackEvent() override;
 
     static PassRefPtrWillBeRawPtr<TrackEvent> create()
     {
         return adoptRefWillBeNoop(new TrackEvent);
     }
 
     static PassRefPtrWillBeRawPtr<TrackEvent> create(const AtomicString& type, const TrackEventInit& initializer)
     {
         return adoptRefWillBeNoop(new TrackEvent(type, initializer));
     }
 
     template <typename T>
     static PassRefPtrWillBeRawPtr<TrackEvent> create(const AtomicString& type, PassRefPtrWillBeRawPtr<T> track)
     {
         return adoptRefWillBeNoop(new TrackEvent(type, track));
     }
 
-    virtual const AtomicString& interfaceName() const override;
+    const AtomicString& interfaceName() const override;
 
     void track(VideoTrackOrAudioTrackOrTextTrack&);
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     TrackEvent();
     TrackEvent(const AtomicString& type, const TrackEventInit& initializer);
     template <typename T>
     TrackEvent(const AtomicString& type, PassRefPtrWillBeRawPtr<T> track)
         : Event(type, false, false)
         , m_track(track)
     {
     }
 
     RefPtrWillBeMember<TrackBase> m_track;
 };
 
 } // namespace blink
 
 #endif // TrackEvent_h