Update documentation for "close".

sdk/lib/async/broadcast_stream_controller.dart

Index: sdk/lib/async/broadcast_stream_controller.dart
diff --git a/sdk/lib/async/broadcast_stream_controller.dart b/sdk/lib/async/broadcast_stream_controller.dart
index 18ff6543f1067fb57f2cee52b341e4dbe20fc3da..89ff7b31f18db61eb5dea1b30325fc700a1b25ac 100644
--- a/sdk/lib/async/broadcast_stream_controller.dart
+++ b/sdk/lib/async/broadcast_stream_controller.dart
@@ -180,11 +180,12 @@ abstract class _BroadcastStreamController<T>
   // _StreamControllerLifecycle interface.
 
   StreamSubscription<T> _subscribe(bool cancelOnError) {
-    if (isClosed) {
-      throw new StateError("Subscribing to closed stream");
-    }
     StreamSubscription subscription =
         new _BroadcastSubscription<T>(this, cancelOnError);
+    if (isClosed) {
+      subscription._addPending(const _DelayedDone());
+      return subscription;
+    }
     _addListener(subscription);
     if (identical(_next, _previous)) {
       // Only one listener, so it must be the first listener.
@@ -313,7 +314,7 @@ abstract class _BroadcastStreamController<T>
     }
   }
 
-  void _callOnCancel() {
+  Future _callOnCancel() {

[Anders Johnsen, 2014/06/02 08:22:50]

I see no return statements?

[Lasse Reichstein Nielsen, 2014/06/02 09:48:25]

And I don't remember making this change. Odd.

     assert(_isEmpty);
     if (isClosed && _doneFuture._mayComplete) {
       // When closed, _doneFuture is not null.