port TemplateBinding to ed3266266e751b5ab1f75f8e0509d0d5f0ef35d8

pkg/template_binding/lib/src/element.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 template_binding;
 
 /** Extensions to the [Element] API. */
 class _ElementExtension extends NodeBindExtension {
   _ElementExtension(Element node) : super._(node);
 
   NodeBinding bind(String name, model, [String path]) {
     _self.unbind(name);
 
     var binding;
     if (_node is OptionElement && name == 'value') {
       // Note: because <option> can be a semantic template, <option> will be
       // a TemplateBindExtension sometimes. So we need to handle it here.
-      _node.attributes.remove(name);
+      (_node as OptionElement).attributes.remove(name);
       binding = new _OptionValueBinding(_node, model, path);
     } else {
       binding = new _AttributeBinding(_node, name, model, path);
     }
     return bindings[name] = binding;
   }
 }
 
 class _AttributeBinding extends NodeBinding {
   final bool conditional;
@@ skipping 45 matching lines @@
     }
 
     super.valueChanged(newValue);
 
     if (selectBinding != null && !selectBinding.closed &&
         select.value != oldValue) {
       selectBinding.nodeValueChanged(null);
     }
   }
 }