node.cloneNode() should clone the value of file upload elements

Source/core/html/HTMLInputElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Samsung Electronics. 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
@@ skipping 184 matching lines @@
     void setSize(unsigned);
     void setSize(unsigned, ExceptionState&);
 
     KURL src() const;
 
     int maxLength() const;
     void setMaxLength(int, ExceptionState&);
 
     bool multiple() const;
 
-    FileList* files();
+    FileList* files() const;
     void setFiles(PassRefPtrWillBeRawPtr<FileList>);
 
     // Returns true if the given DragData has more than one dropped files.
     bool receiveDroppedFiles(const DragData*);
 
     String droppedFileSystemId();
 
     // These functions are used for rendering the input active during a
     // drag-and-drop operation.
     bool canReceiveDroppedFiles() const;
@@ skipping 183 matching lines @@
     RefPtr<InputTypeView> m_inputTypeView;
     // The ImageLoader must be owned by this element because the loader code assumes
     // that it lives as long as its owning element lives. If we move the loader into
     // the ImageInput object we may delete the loader while this element lives on.
     OwnPtr<HTMLImageLoader> m_imageLoader;
     OwnPtr<ListAttributeTargetObserver> m_listAttributeTargetObserver;
 };
 
 } //namespace
 #endif