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

Source/core/html/HTMLDetailsElement.h

 /*
  * Copyright (C) 2010, 2011 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 15 matching lines @@
 namespace blink {
 
 template<typename T> class EventSender;
 typedef EventSender<HTMLDetailsElement> DetailsEventSender;
 
 class HTMLDetailsElement final : public HTMLElement {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<HTMLDetailsElement> create(Document&);
     void toggleOpen();
-    virtual ~HTMLDetailsElement();
+    ~HTMLDetailsElement() override;
 
     void dispatchPendingEvent(DetailsEventSender*);
 
     Element* findMainSummary() const;
 
 private:
     explicit HTMLDetailsElement(Document&);
 
-    virtual LayoutObject* createLayoutObject(const ComputedStyle&) override;
-    virtual void parseAttribute(const QualifiedName&, const AtomicString&) override;
-    virtual void didAddUserAgentShadowRoot(ShadowRoot&) override;
-    virtual bool isInteractiveContent() const override;
+    LayoutObject* createLayoutObject(const ComputedStyle&) override;
+    void parseAttribute(const QualifiedName&, const AtomicString&) override;
+    void didAddUserAgentShadowRoot(ShadowRoot&) override;
+    bool isInteractiveContent() const override;
 
     bool m_isOpen;
 };
 
 } // namespace blink
 
 #endif // HTMLDetailsElement_h