fix parsing of semantic template interation w/ shadowdom polyfill

pkg/mdv/test/mdv_test_utils.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.
 
 library observe_utils;
 
 import 'dart:async';
+import 'dart:html';
 import 'package:observe/observe.dart';
 import 'package:unittest/unittest.dart';
 
+final bool parserHasNativeTemplate = () {
+  var div = new DivElement()..innerHtml = '<table><template>';
+  return div.firstChild.firstChild != null &&
+      div.firstChild.firstChild.tagName == 'TEMPLATE';
+}();
+
 toSymbolMap(Map map) {
   var result = new ObservableMap.linked();
   map.forEach((key, value) {
     if (value is Map) value = toSymbolMap(value);
     result[new Symbol(key)] = value;
   });
   return result;
 }
 
 class FooBarModel extends ObservableBase {
@@ skipping 52 matching lines @@
       } finally {
         performMicrotaskCheckpoint();
       }
     }, onRunAsync: (callback) => _pending.add(callback));
   };
 }
 
 observeTest(name, testCase) => test(name, wrapMicrotask(testCase));
 
 solo_observeTest(name, testCase) => solo_test(name, wrapMicrotask(testCase));