Add zone support to streams.

tests/lib/async/catch_errors21_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 = [];
+  var controller = new StreamController();
+  // Test that stream errors, as a result of bad user-code (`map`) are correctly
+  // caught by `catchErrors`. Note that the values are added outside both
+  // `catchErrors`, but since the `listen` happens in the most nested
+  // `catchErrors` it is caught there.
+  catchErrors(() {
+    catchErrors(() {
+      controller.stream.map((x) { throw x; }).listen((x) {
+        // Should not happen.
+        events.add("bad: $x");
+      });
+    }).listen((x) { events.add("caught: $x"); },
+              onDone: () { events.add("done"); });
+  }).listen((x) { events.add("outer: $x"); },
+            onDone: () {
+              Expect.listEquals(["caught: 1",
+                                 "caught: 2",
+                                 "caught: 3",
+                                 "caught: 4",
+                                 "done",
+                                ],
+                                events);
+              port.close();
+            });
+  [1, 2, 3, 4].forEach(controller.add);
+  controller.close();
+}