Add zone support to streams.

tests/lib/async/catch_errors24_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 "package:expect/expect.dart";
+import 'dart:async';
+import 'dart:isolate';
+
+main() {
+  // We keep a ReceivePort open until all tests are done. This way the VM will
+  // time out if the callbacks are not invoked.
+  var port = new ReceivePort();
+  var events = [];
+  StreamController controller;
+  Stream stream;
+  // Test that the first listen on a `asBroadcastStream` determines the
+  // zone the subscription lives in. In this case the outer listen happens first
+  // and the error reaches `handleError`.
+  catchErrors(() {
+    catchErrors(() {
+      controller = new StreamController();
+      stream = controller.stream
+        .map((x) {
+          events.add("map $x");
+          return x + 100;
+        })
+        .transform(new StreamTransformer(
+            handleError: (e, sink) => sink.add("error $e")))
+        .asBroadcastStream();
+      runAsync(() { stream.listen((x) { events.add("stream $x"); }); });
+    }).listen((x) { events.add(x); })
+      .asFuture().then((_) { events.add("inner done"); });
+    stream.listen((x) { events.add("stream2 $x"); });
+    runAsync(() {
+      controller.add(1);
+      // Errors are not allowed to traverse boundaries, but in this case the
+      // first listener of the broadcast stream is in the same error-zone. So
+      // this should work.
+      controller.addError(2);
+      controller.close();
+    });
+  }).listen((x) { events.add("outer: $x"); },
+            onDone: () {
+      Expect.listEquals([

[Lasse Reichstein Nielsen, 2013/05/29 08:32:26]

Indent to 2 after onDone starts.

[floitsch, 2013/05/29 15:48:56]

Done.

+                         "map 1",
+                         "stream2 101",
+                         "stream 101",
+                         "stream2 error 2",
+                         "stream error 2",
+                         "inner done",
+                         ],

[Lasse Reichstein Nielsen, 2013/05/29 08:32:26]

Unindent by 1.

[floitsch, 2013/05/29 15:48:56]

Done.

+                         events);
+      port.close();
+    });
+}