Expose Zones.

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"; }));
+                runZoned(() => 499,
+                         onError: (e) { throw "Unexpected"; }));
 }