Remove XMLTreeViewer virtual destructor

Source/core/xml/XMLTreeViewer.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:
  *
  * 1. Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *
@@ skipping 18 matching lines @@
 #ifndef XMLTreeViewer_h
 #define XMLTreeViewer_h
 
 namespace WebCore {
 
 class Document;
 
 class XMLTreeViewer {
 public:
     explicit XMLTreeViewer(Document*);
-    virtual ~XMLTreeViewer() {};
 
     void transformDocumentToTreeView();
 
 private:
     Document* m_document;
 };
 
 } // namespace WebCore
 
 #endif // XMLTreeViewer_h