Remove deprecated parts of dart:async.

pkg/observe/lib/src/microtask.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.
 
 /**
  * *Warning*: this library is **internal**, and APIs are subject to change.
  *
  * Wraps a callback using [wrapMicrotask] and provides the ability to pump all
  * observable objects and [scheduleMicrotask] calls via
  * [performMicrotaskCheckpoint].
  */
 library observe.src.microtask;
 
-import 'dart:async' show Completer, runZonedExperimental;
+import 'dart:async' show Completer, runZoned, ZoneSpecification;
 import 'dart:collection';
 import 'package:observe/observe.dart' show Observable;
 
 // TODO(jmesserly): remove "microtask" from these names and instead import
 // the library "as microtask"?
 
 /**
  * This change pumps events relevant to observers and data-binding tests.
  * This must be used inside an [observeTest].
  *
@@ skipping 29 matching lines @@
  * Wraps the [body] in a zone that supports [performMicrotaskCheckpoint],
  * and returns the body.
  */
 // TODO(jmesserly): deprecate? this doesn't add much over runMicrotask.
 wrapMicrotask(body()) => () => runMicrotask(body);
 
 /**
  * Runs the [body] in a zone that supports [performMicrotaskCheckpoint],
  * and returns the result.
  */
-runMicrotask(body()) => runZonedExperimental(() {
+runMicrotask(body()) => runZoned(() {
   try {
     return body();
   } finally {
     performMicrotaskCheckpoint();
   }
-}, onRunAsync: (callback) => _pending.add(callback));
+}, zoneSpecification: new ZoneSpecification(
+    scheduleMicrotask: (self, parent, zone, callback) => _pending.add(callback))
+);