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

Source/core/html/HTMLTrackElement.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 41 matching lines @@
     };
     ReadyState readyState();
     void scheduleLoad();
 
     TextTrack* track();
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit HTMLTrackElement(Document&);
-    virtual ~HTMLTrackElement();
+    ~HTMLTrackElement() override;
 
-    virtual void parseAttribute(const QualifiedName&, const AtomicString&) override;
+    void parseAttribute(const QualifiedName&, const AtomicString&) override;
 
-    virtual InsertionNotificationRequest insertedInto(ContainerNode*) override;
+    InsertionNotificationRequest insertedInto(ContainerNode*) override;
 
-    virtual void removedFrom(ContainerNode*) override;
-    virtual bool isURLAttribute(const Attribute&) const override;
+    void removedFrom(ContainerNode*) override;
+    bool isURLAttribute(const Attribute&) const override;
 
     // TextTrackLoaderClient
-    virtual void newCuesAvailable(TextTrackLoader*) override;
-    virtual void cueLoadingCompleted(TextTrackLoader*, bool loadingFailed) override;
-    virtual void newRegionsAvailable(TextTrackLoader*) override;
+    void newCuesAvailable(TextTrackLoader*) override;
+    void cueLoadingCompleted(TextTrackLoader*, bool loadingFailed) override;
+    void newRegionsAvailable(TextTrackLoader*) override;
 
     void setReadyState(ReadyState);
 
     const AtomicString& mediaElementCrossOriginAttribute() const;
     bool canLoadUrl(const KURL&);
     void loadTimerFired(Timer<HTMLTrackElement>*);
 
     enum LoadStatus {
         Failure,
         Success
     };
     void didCompleteLoad(LoadStatus);
 
     HTMLMediaElement* mediaElement() const;
 
     LoadableTextTrack* ensureTrack();
 
     RefPtrWillBeMember<LoadableTextTrack> m_track;
     OwnPtrWillBeMember<TextTrackLoader> m_loader;
     Timer<HTMLTrackElement> m_loadTimer;
     KURL m_url;
 };
 
 } // namespace blink
 
 #endif // HTMLTrackElement_h