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

Source/core/html/HTMLContentElement.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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 32 matching lines @@
     virtual ~HTMLContentSelectFilter() { }
     virtual bool canSelectNode(const WillBeHeapVector<RawPtrWillBeMember<Node>, 32>& siblings, int nth) const = 0;
 
     DEFINE_INLINE_VIRTUAL_TRACE() { }
 };
 
 class CORE_EXPORT HTMLContentElement final : public InsertionPoint {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<HTMLContentElement> create(Document&, PassOwnPtrWillBeRawPtr<HTMLContentSelectFilter> = nullptr);
-    virtual ~HTMLContentElement();
+    ~HTMLContentElement() override;
 
-    virtual bool canAffectSelector() const override { return true; }
+    bool canAffectSelector() const override { return true; }
 
     bool canSelectNode(const WillBeHeapVector<RawPtrWillBeMember<Node>, 32>& siblings, int nth) const;
 
     const CSSSelectorList& selectorList() const;
     bool isSelectValid() const;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     HTMLContentElement(Document&, PassOwnPtrWillBeRawPtr<HTMLContentSelectFilter>);
 
-    virtual void parseAttribute(const QualifiedName&, const AtomicString&) override;
+    void parseAttribute(const QualifiedName&, const AtomicString&) override;
 
     bool validateSelect() const;
     void parseSelect();
 
     bool matchSelector(Element&) const;
 
     bool m_shouldParseSelect;
     bool m_isValidSelector;
     AtomicString m_select;
     CSSSelectorList m_selectorList;
@@ skipping 23 matching lines @@
     if (!isSelectValid())
         return false;
     if (!siblings[nth]->isElementNode())
         return false;
     return matchSelector(*toElement(siblings[nth]));
 }
 
 } // namespace blink
 
 #endif // HTMLContentElement_h