implement dirty checking for @observable objects

pkg/mdv/lib/src/bindings.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 mdv;
 
 // This code is a port of Model-Driven-Views:
 // https://github.com/polymer-project/mdv
 // The code mostly comes from src/template_element.js
 
@@ skipping 228 matching lines @@
   final Element _templateElement;
   final List<Node> terminators = [];
   final CompoundBinding inputs;
   List iteratedValue;
   Object _lastValue;
 
   StreamSubscription _sub;
   StreamSubscription _valueBinding;
 
   _TemplateIterator(this._templateElement)
-    : inputs = new CompoundBinding(resolveInputs) {
+      : inputs = new CompoundBinding(resolveInputs) {
 
     _valueBinding = new PathObserver(inputs, 'value').bindSync(valueChanged);
   }
 
   static Object resolveInputs(Map values) {
     if (values.containsKey('if') && !_toBoolean(values['if'])) {
       return null;
     }
 
     if (values.containsKey('repeat')) {
@@ skipping 161 matching lines @@
         nodeExt._templateIterator = null;
       }
     }
 
     _nodeOrCustom(node).unbindAll();
     for (var c = node.firstChild; c != null; c = c.nextNode) {
       _unbindAllRecursively(c);
     }
   }
 }