Let Node.nodeName never return null

Source/core/dom/Node.idl

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 18 matching lines @@
     const unsigned short      CDATA_SECTION_NODE             = 4;
     const unsigned short      ENTITY_REFERENCE_NODE          = 5; // EntityReference nodes are impossible to create in WebKit.
     const unsigned short      ENTITY_NODE                    = 6;
     const unsigned short      PROCESSING_INSTRUCTION_NODE    = 7;
     const unsigned short      COMMENT_NODE                   = 8;
     const unsigned short      DOCUMENT_NODE                  = 9;
     const unsigned short      DOCUMENT_TYPE_NODE             = 10;
     const unsigned short      DOCUMENT_FRAGMENT_NODE         = 11;
     const unsigned short      NOTATION_NODE                  = 12;
 
-    [TreatReturnedNullStringAs=Null, PerWorldBindings] readonly attribute DOMString        nodeName;
+    [PerWorldBindings] readonly attribute DOMString nodeName;
 
-             // FIXME: the spec says this can also raise on retrieval.
     [TreatReturnedNullStringAs=Null, TreatNullAs=NullString, PerWorldBindings, CustomElementCallbacks] attribute DOMString nodeValue;
 
     [PerWorldBindings] readonly attribute unsigned short   nodeType;
     [PerWorldBindings] readonly attribute Node             parentNode;
     [PerWorldBindings] readonly attribute NodeList         childNodes;
     [PerWorldBindings] readonly attribute Node             firstChild;
     [PerWorldBindings] readonly attribute Node             lastChild;
     [PerWorldBindings] readonly attribute Node             previousSibling;
     [PerWorldBindings] readonly attribute Node             nextSibling;
     [PerWorldBindings] readonly attribute Document         ownerDocument;
@@ skipping 37 matching lines @@
     const unsigned short      DOCUMENT_POSITION_IMPLEMENTATION_SPECIFIC = 0x20;
 
     unsigned short     compareDocumentPosition([Default=Undefined] optional Node other);
 
     // Introduced in DOM4
     [ImplementedAs=bindingsContains] boolean contains([Default=Undefined] optional Node other);
 
     // IE extensions
     [PerWorldBindings] readonly attribute Element          parentElement;
 };