Add zone support to streams.

tests/lib/async/catch_errors23_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
+  // hang if the callbacks are not invoked and the test will time out.
+  var port = new ReceivePort();
+  var events = [];
+  StreamController controller;
+  Stream stream;
+  // Test that errors are not traversing zone boundaries.
+  // Note that the first listener of `asBroadcastStream` determines in which
+  // zone the subscription lives.
+  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();
+      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"); });
+    controller.add(1);
+    // Errors are not allowed to traverse boundaries. This error should be
+    // caught by the outer catchErrors.
+    controller.addError(2);
+    controller.close();
+  }).listen((x) { events.add("outer: $x"); },
+            onDone: () {
+              Expect.listEquals(["map 1",
+                                "stream 101",
+                                "stream2 101",
+                                "outer: 2",
+                                "inner done",
+                                ],
+                                events);
+              port.close();
+            });
+}