Converting tests over to using event streams.

tests/html/event_customevent_test.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.
 
 library EventCustomEventTest;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
 
 // TODO(nweiz): Make this private to testEvents when Frog supports closures with
 // optional arguments.
 eventTest(String name, Event eventFn(), void validate(Event),
     [String type = 'foo']) {
   test(name, () {
     final el = new Element.tag('div');
     var fired = false;
     el.on[type].add((ev) {
       fired = true;
       validate(ev);
     });
     el.on[type].dispatch(eventFn());
     expect(fired, isTrue, reason: 'Expected event to be dispatched.');
   });
 }
 
 main() {
   useHtmlConfiguration();
 
-  eventTest('CustomEvent.initCustomEvent', () {
-    return new CustomEvent('foo', canBubble: false, cancelable: false,
+  test('custom events', () {
+    var provider = new EventStreamProvider<CustomEvent>('foo');
+    var el = new DivElement();
+
+    var fired = false;
+    provider.forTarget(el).listen((ev) {
+      fired = true;
+      expect(ev.detail, 'detail');
+    });
+
+    var ev = new CustomEvent('foo', canBubble: false, cancelable: false,
         detail: 'detail');
-  },
-  (ev) { expect(ev.detail, equals('detail')); });
+    el.dispatchEvent(ev);
+    expect(fired, isTrue);
+  });
 }