Rework Timer interface.

pkg/unittest/test/test_utils.dart

 // Copyright (c) 2012, 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.
 
 part of unittestTests;
 
 int errorCount;
 String errorString;
 var _testHandler = null;
 
 class MyFailureHandler extends DefaultFailureHandler {
   void fail(String reason) {
     ++errorCount;
     errorString = reason;
   }
 }
 
 void initUtils() {
   if (_testHandler == null) {
     _testHandler = new MyFailureHandler();
   }
 }
 
 void shouldFail(value, Matcher matcher, expected, {bool isAsync: false}) {
   configureExpectFailureHandler(_testHandler);
   errorCount = 0;
   errorString = '';
   expect(value, matcher);
-  afterTest(_) {
+  afterTest() {
     configureExpectFailureHandler(null);
     expect(errorCount, equals(1));
     if (expected is String) {
       expect(errorString, equalsIgnoringWhitespace(expected));
     } else {
      expect(errorString, expected);
     }
   }
 
   if (isAsync) {
-    new Timer(0, expectAsync1(afterTest));
+    Timer.run(expectAsync0(afterTest));
   } else {
-    afterTest(null);
+    afterTest();
   }
 }
 
 void shouldPass(value, Matcher matcher, {bool isAsync: false}) {
   configureExpectFailureHandler(_testHandler);
   errorCount = 0;
   errorString = '';
   expect(value, matcher);
-  afterTest(_) {
+  afterTest() {
     configureExpectFailureHandler(null);
     expect(errorCount, equals(0));
   }
   if (isAsync) {
-    new Timer(0, expectAsync1(afterTest));
+    Timer.run(expectAsync0(afterTest));
   } else {
-    afterTest(null);
+    afterTest();
   }
 }