package:observe fix various api issues

pkg/observe/lib/src/compound_binding.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.
 
 part of observe;
 
 /** The callback used in the [CompoundBinding.combinator] field. */
 typedef Object CompoundBindingCombinator(Map objects);
 
 /**
  * CompoundBinding is an object which knows how to listen to multiple path
  * values (registered via [bind]) and invoke its [combinator] when one or more
  * of the values have changed and set its [value] property to the return value
  * of the function. When any value has changed, all current values are provided
  * to the [combinator] in the single `values` argument.
  *
  * For example:
  *
  *     var binding = new CompoundBinding((values) {
  *       var combinedValue;
  *       // compute combinedValue based on the current values which are provided
  *       return combinedValue;
  *     });
  *     binding.bind('name1', obj1, path1);
  *     binding.bind('name2', obj2, path2);
  *     //...
  *     binding.bind('nameN', objN, pathN);
  */
 // TODO(jmesserly): rename to something that indicates it's a computed value?
-class CompoundBinding extends ChangeNotifierBase {
+class CompoundBinding extends ChangeNotifier {
   CompoundBindingCombinator _combinator;
 
   // TODO(jmesserly): ideally these would be String keys, but sometimes we
   // use integers.
   Map<dynamic, StreamSubscription> _observers = new Map();
   Map _values = new Map();
   Object _value;
 
   /**
    * True if [resolve] is scheduled. You can set this to true if you plan to
@@ skipping 83 matching lines @@
     for (var binding in _observers.values) {
       binding.cancel();
     }
     _observers.clear();
     _values.clear();
     value = null;
   }
 
   _unobserved() => close();
 }