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

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 22 matching lines @@
 namespace blink {
 
 class HTMLTrackElement;
 
 class LoadableTextTrack final : public TextTrack {
 public:
     static PassRefPtrWillBeRawPtr<LoadableTextTrack> create(HTMLTrackElement* track)
     {
         return adoptRefWillBeNoop(new LoadableTextTrack(track));
     }
-    virtual ~LoadableTextTrack();
+    ~LoadableTextTrack() override;
 
     // TextTrack method.
-    virtual void setMode(const AtomicString&) override;
+    void setMode(const AtomicString&) override;
 
     void addRegions(const WillBeHeapVector<RefPtrWillBeMember<VTTRegion>>&);
     using TextTrack::addListOfCues;
 
     size_t trackElementIndex();
     HTMLTrackElement* trackElement() { return m_trackElement; }
 #if !ENABLE(OILPAN)
     void clearTrackElement();
 #endif
 
-    virtual bool isDefault() const override;
+    bool isDefault() const override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit LoadableTextTrack(HTMLTrackElement*);
 
     RawPtrWillBeMember<HTMLTrackElement> m_trackElement;
 };
 
 } // namespace blink
 
 #endif // LoadableTextTrack_h