Use IDL default argument value for Range.collapse()'s toStart argument

Source/core/dom/Range.idl

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * 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 20 matching lines @@
     readonly attribute long endOffset;
     readonly attribute boolean collapsed;
     readonly attribute Node commonAncestorContainer;
 
     [RaisesException] void setStart(Node refNode, long offset);
     [RaisesException] void setEnd(Node refNode, long offset);
     [RaisesException] void setStartBefore(Node refNode);
     [RaisesException] void setStartAfter(Node refNode);
     [RaisesException] void setEndBefore(Node refNode);
     [RaisesException] void setEndAfter(Node refNode);
-    void collapse([Default=Undefined] optional boolean toStart);
+    void collapse(optional boolean toStart = false);
     [RaisesException] void selectNode(Node refNode);
     [RaisesException] void selectNodeContents(Node refNode);
 
     // CompareHow
     const unsigned short START_TO_START = 0;
     const unsigned short START_TO_END   = 1;
     const unsigned short END_TO_END     = 2;
     const unsigned short END_TO_START   = 3;
 
     [RaisesException] short compareBoundaryPoints(CompareHow how, Range sourceRange);
@@ skipping 28 matching lines @@
     // CompareResults
     const unsigned short NODE_BEFORE           = 0;
     const unsigned short NODE_AFTER            = 1;
     const unsigned short NODE_BEFORE_AND_AFTER = 2;
     const unsigned short NODE_INSIDE           = 3;
 
     [RaisesException, MeasureAs=RangeCompareNode] short compareNode([Default=Undefined] optional Node refNode);
 
     [RaisesException, MeasureAs=RangeExpand] void expand([Default=Undefined] optional DOMString unit);
 };