Fix listeners being added to subscription after onListen was called.

tests/lib/async/stream_controller_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.
 
 // Test the basic StreamController and StreamController.singleSubscription.
 library stream_controller_test;
 
 import "package:expect/expect.dart";
 import "package:async_helper/async_helper.dart";
 import 'dart:async';
@@ skipping 639 matching lines @@
       sub.asFuture().whenComplete(() { Expect.fail("Bad complete"); });
       sub.resume();
       new Timer(MS * 100, () {
         sub.onDone(asyncEnd);
         sub.resume();
       });
     });
   });
 }
 
+void testEventInListen() {
+  asyncStart();
+  // Regression test for http://dartbug.com/19722
+  var c;
+  void send() {
+    c.add(1);
+  }
+  int i = 1;
+  c = new StreamController.broadcast(onListen: send, sync: true);
+  c.stream.listen((v) {
+    Expect.equals(i++, v);
+  }, onDone: asyncEnd);
+  c.add(2);
+  c.close();
+}
+
 main() {
   asyncStart();
   testMultiController();
   testSingleController();
   testExtraMethods();
   testClosed();
   testCloseFuture();
   testCloseFuture2();
   testCloseFuture3();
   testStreamEquals();
   testCancelThrow();
   testCancelThrow2();
   testCancelThrow3();
   testBroadcastListenAfterClose();
   testBroadcastListenAfterClosePaused();
   testAsBroadcastListenAfterClose();
   testAsBroadcastListenAfterClosePaused();
+  testEventInListen();
   asyncEnd();
 }