Remove StreamController.broadcast.

tools/dom/templates/html/impl/impl_Window.darttemplate

 // 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 $LIBRARYNAME;
 
 $if DART2JS
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS native "@*DOMWindow" {
 $else
 $(ANNOTATIONS)class $CLASSNAME$EXTENDS$IMPLEMENTS$NATIVESPEC {
@@ skipping 297 matching lines @@
   }
 }
 
 class _BeforeUnloadEventStreamProvider implements
     EventStreamProvider<BeforeUnloadEvent> {
   final String _eventType;
 
   const _BeforeUnloadEventStreamProvider(this._eventType);
 
   Stream<BeforeUnloadEvent> forTarget(EventTarget e, {bool useCapture: false}) {
-    var controller = new StreamController.broadcast();
+    var controller = new StreamController();
     var stream = new _EventStream(e, _eventType, useCapture);
     stream.listen((event) {
       var wrapped = new _BeforeUnloadEvent(event);
       controller.add(wrapped);
       return wrapped.returnValue;
     });
 
     return controller.stream;

[Anders Johnsen, 2013/04/15 10:22:34]

.asBroadcastStream?

[floitsch, 2013/04/15 22:58:12]

No. I prefer if HTML controllers are single subscription.

   }
 
   String getEventType(EventTarget target) {
     return _eventType;
   }
 }