IDL: make optional arguments (without default) explicit sometimes

Source/core/xml/XPathEvaluator.idl

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  *
  * 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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 [
     WillBeGarbageCollected,
     Constructor
 ] interface XPathEvaluator {
-    [RaisesException] XPathExpression createExpression([Default=Undefined] optional DOMString expression,
-                                     [Default=Undefined] optional XPathNSResolver resolver);
+    [RaisesException] XPathExpression createExpression(optional DOMString expression,
+                                     optional XPathNSResolver resolver);
 
-    XPathNSResolver createNSResolver([Default=Undefined] optional Node nodeResolver);
+    XPathNSResolver createNSResolver(optional Node nodeResolver);
 
-    [RaisesException] XPathResult evaluate([Default=Undefined] optional DOMString expression,
-                         [Default=Undefined] optional Node contextNode,
-                         [Default=Undefined] optional XPathNSResolver resolver,
-                         [Default=Undefined] optional unsigned short type,
-                         [Default=Undefined] optional XPathResult inResult);
+    [RaisesException] XPathResult evaluate(optional DOMString expression,
+                         optional Node contextNode,
+                         optional XPathNSResolver resolver,
+                         optional unsigned short type,
+                         optional XPathResult inResult);
 };