IDL: make optional arguments (without default) explicit sometimes

Source/core/xml/XSLTProcessor.idl

 /*
  * Copyright (C) 2008, 2010 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
@@ skipping 19 matching lines @@
 // http://lxr.mozilla.org/seamonkey/source/content/xsl/public/nsIXSLTException.idl
 // http://bugs.webkit.org/show_bug.cgi?id=5446
 
 [
     WillBeGarbageCollected,
     Constructor,
     RuntimeEnabled=XSLT,
     MeasureAs=XSLTProcessor
 ] interface XSLTProcessor {
 
-    void importStylesheet([Default=Undefined] optional Node stylesheet);
-    [CustomElementCallbacks] DocumentFragment transformToFragment([Default=Undefined] optional Node source, [Default=Undefined] optional Document docVal);
-    [CustomElementCallbacks] Document transformToDocument([Default=Undefined] optional Node source);
+    void importStylesheet(optional Node stylesheet);
+    [CustomElementCallbacks] DocumentFragment transformToFragment(optional Node source, optional Document docVal);
+    [CustomElementCallbacks] Document transformToDocument(optional Node source);
 
     [Custom] void setParameter(DOMString namespaceURI, DOMString localName, DOMString value);
     [Custom, TreatReturnedNullStringAs=Undefined] DOMString getParameter(DOMString namespaceURI, DOMString localName);
     [Custom] void removeParameter(DOMString namespaceURI, DOMString localName);
     void clearParameters();
 
     void reset();
 
 };