Force named arguments in constructors.

tests/html/query_test.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #library('QueryTest');
 #import('../../pkg/unittest/unittest.dart');
 #import('../../pkg/unittest/html_config.dart');
 #import('dart:html');
 
 main() {
   useHtmlConfiguration();
 
   final div = new DivElement();
-  final canvas = new CanvasElement(200,200);
+  final canvas = new CanvasElement(width: 200, height: 200);
   canvas.id = 'testcanvas';
   final element =
       new Element.html("<div><br/><img/><input/><img/></div>");
   document.body.nodes.addAll([div, canvas,  element]);
   
 
   test('query', () {
       Element e = query('#testcanvas');
       Expect.isNotNull(e);
       Expect.stringEquals('testcanvas', e.id);
@@ skipping 19 matching lines @@
       Expect.isTrue(l[0] is ImageElement);
       Expect.isTrue(l[1] is ImageElement);
       Expect.notEquals(l[0], l[1]);
     });
 
   test('queryAll (None)', () {
       List l = queryAll('video');
       Expect.isTrue(l.isEmpty());
     });
 }