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

Source/core/dom/DocumentFragment.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
  *
  * 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.
@@ skipping 20 matching lines @@
 namespace blink {
 
 class CORE_EXPORT DocumentFragment : public ContainerNode {
     DEFINE_WRAPPERTYPEINFO();
 public:
     static PassRefPtrWillBeRawPtr<DocumentFragment> create(Document&);
 
     void parseHTML(const String&, Element* contextElement, ParserContentPolicy = AllowScriptingContent);
     bool parseXML(const String&, Element* contextElement, ParserContentPolicy = AllowScriptingContent);
 
-    virtual bool canContainRangeEndPoint() const override final { return true; }
+    bool canContainRangeEndPoint() const final { return true; }
     virtual bool isTemplateContent() const { return false; }
 
 protected:
     DocumentFragment(Document*, ConstructionType = CreateContainer);
-    virtual String nodeName() const override final;
+    String nodeName() const final;
 
 private:
-    virtual NodeType nodeType() const override final;
-    virtual PassRefPtrWillBeRawPtr<Node> cloneNode(bool deep = true) override;
-    virtual bool childTypeAllowed(NodeType) const override;
+    NodeType nodeType() const final;
+    PassRefPtrWillBeRawPtr<Node> cloneNode(bool deep = true) override;
+    bool childTypeAllowed(NodeType) const override;
 
     bool isDocumentFragment() const = delete; // This will catch anyone doing an unnecessary check.
 };
 
 DEFINE_NODE_TYPE_CASTS(DocumentFragment, isDocumentFragment());
 
 } // namespace blink
 
 #endif // DocumentFragment_h