Fix bug in Blob creation from workers.

tests/lib_strong/html/rtc_test.dart

  // Copyright (c) 2013, 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.
 
 import 'dart:html';
 
 import 'package:expect/minitest.dart';
 
 main() {
   group('supported', () {
     test('supported', () {
       expect(RtcPeerConnection.supported, isTrue);
     });
   });
 
   group('functionality', () {
     // More thorough testing of this API requires the user to
     // explicitly click "allow this site to access my camera and/or microphone."
     // or particularly allow that site to always have those permission on each
     // computer the test is run. For more through tests, see
     // interactive_test.dart.
     if (RtcPeerConnection.supported) {
       test('peer connection', () {
         var pc = new RtcPeerConnection(
             {'iceServers': [ {'url':'stun:216.93.246.18:3478'}]});
         expect(pc is RtcPeerConnection, isTrue);
-        // TODO(efortuna): Uncomment this test when RTCPeerConnection correctly
-        // implements EventListener in Firefox (works correctly in nightly, so
-        // it's coming!).
-        //pc.onIceCandidate.listen((candidate) {});
+        pc.onIceCandidate.listen((candidate) {});
       });
 
       test('ice candidate', () {
         var candidate = new RtcIceCandidate({'sdpMLineIndex' : 1,
                                              'candidate' : 'hello'});
         expect(candidate is RtcIceCandidate, isTrue);
       });
 
       test('session description', () {
         var description = new RtcSessionDescription({'sdp': 'foo',
                                                      'type': 'offer'});
         expect(description is RtcSessionDescription, isTrue);
       });
     }
   });
 }