fix webui for sdk 0.8.7

lib/observe/observable.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.
 
 /**
  * This library is used to implement [Observable] types.
  *
  * It exposes lower level functionality such as [hasObservers], [observeReads]
  * [notifyChange] and [notifyRead].
  *
  * Unless you are mixing in [Observable], it is usually better to write:
  *
  *     import 'package:web_ui/observe.dart';
  */
 library web_ui.observe.observable;
 
+import 'dart:async';
 import 'dart:collection' hide LinkedList;
 import 'list.dart';
 import 'map.dart';
 import 'reference.dart';
 import 'set.dart';
-import 'package:web_ui/src/utils_observe.dart' show setImmediate, hash3, hash4;
+import 'package:web_ui/src/utils_observe.dart' show hash3, hash4;
 import 'package:web_ui/src/linked_list.dart';
 
 /**
  * Use `@observable` to make a class observable. All fields in the class will
  * be transformed to track changes. The overhead will be minimal unless they are
  * actually being observed.
  */
 const observable = const _ObservableAnnotation();
 
 /** Callback fired when an expression changes. */
@@ skipping 304 matching lines @@
 
   // If this is an assignment (and not insert/remove) then check if
   // the value actually changed. If not don't signal a change event.
   // This helps programmers avoid some common cases of cycles in their code.
   if ((type & (ChangeRecord.INSERT | ChangeRecord.REMOVE)) == 0) {
     if (oldValue == newValue) return;
   }
 
   if (_changedObjects == null) {
     _changedObjects = [];
-    setImmediate(deliverChangesSync);
+    runAsync(deliverChangesSync);
   }
   if (self.$_changes == null) {
     self.$_changes = [];
     _changedObjects.add(self);
   }
   self.$_changes.add(new ChangeRecord(type, key, oldValue, newValue));
 }
 
 // Optimizations to avoid extra work if observing const/final data.
 void _doNothing() {}
@@ skipping 328 matching lines @@
 /**
  * The type of the `@observable` annotation.
  *
  * Library private because you should be able to use the [observable] field
  * to get the one and only instance. We could make it public though, if anyone
  * needs it for some reason.
  */
 class _ObservableAnnotation {
   const _ObservableAnnotation();
 }