fix a bug in the Event constructor

tests/html/events_test.dart

 library EventsTest;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
 
 main() {
   useHtmlConfiguration();
+
   test('TimeStamp', () {
     Event event = new Event('test');
 
     int timeStamp = event.timeStamp;
     expect(timeStamp, greaterThan(0));
   });
+
+  test('Event canBubble and cancelable', () {
+    // Try every combination of canBubble and cancelable
+    for (var i = 0; i < 4; i++) {
+      var bubble = (i & 1) != 0;
+      var cancel = (i & 2) != 0;
+      var e = new Event('input', canBubble: bubble, cancelable: cancel);
+      expect(e.bubbles, bubble, reason: 'canBubble was set to $bubble');
+      expect(e.cancelable, cancel, reason: 'cancelable was set to $cancel');
+    }
+  });
+
   // The next test is not asynchronous because [on['test'].dispatch(event)] fires the event
   // and event listener synchronously.
   test('EventTarget', () {
     Element element = new Element.tag('test');
     element.id = 'eventtarget';
     window.document.body.nodes.add(element);
 
     int invocationCounter = 0;
     void handler(Event e) {
       expect(e.type, equals('test'));
@@ skipping 23 matching lines @@
     provider.forTarget(element).listen(handler);
     invocationCounter = 0;
     element.dispatchEvent(event);
     expect(invocationCounter, 1);
 
     provider.forTarget(element).listen(handler);
     invocationCounter = 0;
     element.dispatchEvent(event);
     expect(invocationCounter, 1);
   });
+
   test('InitMouseEvent', () {
     DivElement div = new Element.tag('div');
     MouseEvent event = new MouseEvent('zebra', relatedTarget: div);
   });
 }