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

Source/core/html/HTMLAudioElement.h

 /*
  * Copyright (C) 2007, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2010 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
@@ skipping 21 matching lines @@
 namespace blink {
 
 class Document;
 
 class HTMLAudioElement final : public HTMLMediaElement {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<HTMLAudioElement> create(Document&);
     static PassRefPtrWillBeRawPtr<HTMLAudioElement> createForJSConstructor(Document&, const AtomicString& src);
 
-    virtual bool isHTMLAudioElement() const override { return true; }
+    bool isHTMLAudioElement() const override { return true; }
 
 private:
     HTMLAudioElement(Document&);
 };
 
 } // namespace blink
 
 #endif // HTMLAudioElement_h