[DOM4] Have ProcessingInstruction inherit CharacterData

Source/core/dom/CharacterData.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2008, 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 48 matching lines @@
         ScriptWrappable::init(this);
     }
 
     void setDataWithoutUpdate(const String& data)
     {
         ASSERT(!data.isNull());
         m_data = data;
     }
     void didModifyData(const String& oldValue);
 
+    String m_data;
+
 private:
     virtual String nodeValue() const OVERRIDE FINAL;
     virtual void setNodeValue(const String&) OVERRIDE FINAL;
     virtual bool isCharacterDataNode() const OVERRIDE FINAL { return true; }
     virtual int maxCharacterOffset() const OVERRIDE FINAL;
     virtual bool offsetInCharacters() const OVERRIDE FINAL;
     void setDataAndUpdate(const String&, unsigned offsetOfReplacedData, unsigned oldLength, unsigned newLength);
-
-    String m_data;
 };
 
 } // namespace WebCore
 
 #endif // CharacterData_h