Reapply "Zone support for Futures, Timer, Streams."

tests/lib/async/run_zoned4_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';
+
+main() {
+  // Make sure `runZoned` returns the result of a synchronous call when an
+  // error handler is defined.
+  Expect.equals(499,
+                runZonedExperimental(() => 499,
+                                     onError: (e) { throw "Unexpected"; }));
+}