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

Source/core/html/track/VideoTrackList.h

Index: Source/core/html/track/VideoTrackList.h
diff --git a/Source/core/html/track/VideoTrackList.h b/Source/core/html/track/VideoTrackList.h
index 6fe92b9cbb334c010af9a514dc2b8e56c140c929..991abbc347bc01c79928499e2c6a31e543d4246b 100644
--- a/Source/core/html/track/VideoTrackList.h
+++ b/Source/core/html/track/VideoTrackList.h
@@ -15,12 +15,12 @@ class VideoTrackList final : public TrackListBase<VideoTrack> {
 public:
     static PassRefPtrWillBeRawPtr<VideoTrackList> create(HTMLMediaElement&);
 
-    virtual ~VideoTrackList();
+    ~VideoTrackList() override;
 
     int selectedIndex() const;
 
     // EventTarget
-    virtual const AtomicString& interfaceName() const override;
+    const AtomicString& interfaceName() const override;
 
     void trackSelected(WebMediaPlayer::TrackId selectedTrackId);