WebUI fixes for SDK 0.8.10

lib/observe/set.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.
 
 library web_ui.observe.set;
 
 import 'dart:collection';
 import 'observable.dart';
 import 'map.dart' show MapFactory;
-import 'package:web_ui/src/utils_observe.dart' show IterableWorkaround;
 
 /**
  * Represents an observable set of model values. If any items are added,
  * removed, or replaced, then observers that are registered with
  * [observe] will be notified.
  */
 // TODO(jmesserly): ideally this could be based ObservableMap, or Dart
 // would have a built in Set<->Map adapter as suggested in
 // https://code.google.com/p/dart/issues/detail?id=5603
-class ObservableSet<E> extends IterableWorkaround with Observable
-    implements Set<E> {
+class ObservableSet<E> extends IterableBase<E> with Observable {
 
   final Map<E, Object> _map;
 
   final MapFactory<E, Object> _createMap;
 
   /**
    * Creates an observable set, optionally using the provided [createMap]
    * factory to construct a custom map type.
    */
   ObservableSet({MapFactory<E, Object> createMap})
@@ skipping 152 matching lines @@
     _set.length;
     return _hasNext = _iterator.moveNext();
   }
 
   E get current {
     var result = _iterator.current;
     if (observeReads && _hasNext) notifyRead(_set, ChangeRecord.INDEX, result);
     return result;
   }
 }