[mdv] fix checked mode issue

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);
 
 /**
@@ skipping 25 matching lines @@
   Map _values = new Map();
   Object _value;
 
   /**
    * True if [resolve] is scheduled. You can set this to true if you plan to
    * call [resolve] manually, avoiding the need for scheduling an asynchronous
    * resolve.
    */
   // TODO(jmesserly): I don't like having this public, is the optimization
   // really needed? "runAsync" in Dart should be pretty cheap.
-  bool scheduled;
+  bool scheduled = false;
 
   /**
    * Creates a new CompoundBinding, optionally proving the [combinator] function
    * for computing the value. You can also set [schedule] to true if you plan
    * to invoke [resolve] manually after initial construction of the binding.
    */
   CompoundBinding([CompoundBindingCombinator combinator]) {
     // TODO(jmesserly): this is a tweak to the original code, it seemed to me
     // that passing the combinator to the constructor should be equivalent to
     // setting it via the property.
@@ skipping 69 matching lines @@
     for (var binding in _observers.values) {
       binding.cancel();
     }
     _observers.clear();
     _values.clear();
     value = null;
   }
 
   _unobserved() => close();
 }