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

Source/core/html/PluginDocument.h

 /*
  * Copyright (C) 2006, 2008, 2009 Apple 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 27 matching lines @@
     static PassRefPtrWillBeRawPtr<PluginDocument> create(const DocumentInit& initializer = DocumentInit())
     {
         return adoptRefWillBeNoop(new PluginDocument(initializer));
     }
 
     void setPluginNode(Node* pluginNode) { m_pluginNode = pluginNode; }
 
     Widget* pluginWidget();
     Node* pluginNode();
 
-    virtual void detach(const AttachContext& = AttachContext()) override;
+    void detach(const AttachContext& = AttachContext()) override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
     explicit PluginDocument(const DocumentInit&);
 
-    virtual PassRefPtrWillBeRawPtr<DocumentParser> createParser() override;
+    PassRefPtrWillBeRawPtr<DocumentParser> createParser() override;
 
     RefPtrWillBeMember<Node> m_pluginNode;
 };
 
 DEFINE_DOCUMENT_TYPE_CASTS(PluginDocument);
 
 }
 
 #endif // PluginDocument_h