Modified unittest to use new argument syntax.

tests/html/element_webkit_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('ElementWebKitTest');
 #import('../../pkg/unittest/unittest.dart');
 #import('../../pkg/unittest/html_config.dart');
 #import('dart:html');
 
 
@@ skipping 19 matching lines @@
   });
   if (registerOnEventListener != null) {
     registerOnEventListener((e) {
       firedOnEvent = true;
     });
   }
 
   final event = new Event(type);
   listenerList.dispatch(event);
 
-  Expect.isTrue(firedWhenAddedToListenerList);
+  expect(firedWhenAddedToListenerList, isTrue);
   if (registerOnEventListener != null) {
-    Expect.isTrue(firedOnEvent);
+    expect(firedOnEvent, isTrue);
   }
 }
 
 main() {
   useHtmlConfiguration();
 
   group('constructors', () {
     test('details', () => testConstructorHelper('details',
         '<details>foo</details>', 'foo',
         (element) => element is DetailsElement));
@@ skipping 18 matching lines @@
     final on = element.on;
     testEventHelper(on.transitionEnd, 'webkitTransitionEnd');
     testEventHelper(on.fullscreenChange, 'webkitfullscreenchange',
         (listener) => Testing.addEventListener(element,
             'webkitfullscreenchange', listener, true));
   });
 }