Fix bugs in StreamController.addStream.

sdk/lib/async/broadcast_stream_controller.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 dart.async;
 
 class _BroadcastStream<T> extends _ControllerStream<T> {
   _BroadcastStream(_StreamControllerLifecycle controller) : super(controller);
 
   bool get isBroadcast => true;
@@ skipping 220 matching lines @@
     }
     if (!_mayAddEvent) throw _addEventError();
     _state |= _STATE_CLOSED;
     Future doneFuture = _ensureDoneFuture();
     _sendDone();
     return doneFuture;
   }
 
   Future get done => _ensureDoneFuture();
 
-  Future addStream(Stream<T> stream) {
+  Future addStream(Stream<T> stream, {bool cancelOnError: true}) {
     if (!_mayAddEvent) throw _addEventError();
     _state |= _STATE_ADDSTREAM;
-    _addStreamState = new _AddStreamState(this, stream);
+    _addStreamState = new _AddStreamState(this, stream, cancelOnError);
     return _addStreamState.addStreamFuture;
   }
 
   // _EventSink interface, called from AddStreamState.
   void _add(T data) {
     _sendData(data);
   }
 
   void _addError(Object error, StackTrace stackTrace) {
     assert(_isAddingStream);
@@ skipping 214 matching lines @@
     _pauseCount++;
   }
   void resume() { _resume(null); }
   void _resume(_) {
     if (_pauseCount > 0) _pauseCount--;
   }
   void cancel() {}
   bool get isPaused => _pauseCount > 0;
   Future asFuture([Object value]) => new _Future();
 }