Ensure model is passed with <template if>

pkg/mdv/lib/src/template_iterator.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 25 matching lines @@
   } else if (node is Text) {
     _parseAndBind(node, 'text', node.text, model, delegate);
   }
 
   for (var c = node.firstChild; c != null; c = c.nextNode) {
     _addBindings(c, model, delegate);
   }
 }
 
 void _addAttributeBindings(Element element, model, delegate) {
-  element.attributes.forEach((name, value) {
-    if (value == '' && (name == 'bind' || name == 'repeat')) {
-      value = '{{}}';
+  var attrs = new LinkedHashMap.from(element.attributes);
+  if (element.isTemplate) {
+    // Accept 'naked' bind & repeat.
+    if (attrs['bind'] == '') attrs['bind'] = '{{}}';
+    if (attrs['repeat'] == '') attrs['repeat'] = '{{}}';
+
+    // Treat <template if="{{expr}}"> as <template bind if="{{expr}}">
+    if (attrs.containsKey('if') &&
+        !attrs.containsKey('bind') &&
+        !attrs.containsKey('repeat')) {
+      attrs['bind'] = '{{}}';
     }
+  }
+
+  attrs.forEach((name, value) {
     _parseAndBind(element, name, value, model, delegate);
   });
 }
 
 void _parseAndBind(Node node, String name, String text, model,
     BindingDelegate delegate) {
 
   var tokens = _parseMustacheTokens(text);
   if (tokens.length == 0 || (tokens.length == 1 && tokens[0].isText)) {
     return;
@@ skipping 315 matching lines @@
         nodeExt._templateIterator = null;
       }
     }
 
     _nodeOrCustom(node).unbindAll();
     for (var c = node.firstChild; c != null; c = c.nextNode) {
       _unbindAllRecursively(c);
     }
   }
 }