port Node.bind to bd0a0591920da9091b326627a46a104a92c7efe7

pkg/template_binding/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 template_binding.test.utils;
 
 import 'dart:html';
 import 'package:observe/observe.dart';
 import 'package:template_binding/template_binding.dart';
 import 'package:unittest/unittest.dart';
@@ skipping 76 matching lines @@
 
   return root;
 }
 
 /**
  * Sanitizer which does nothing.
  */
 class NullTreeSanitizer implements NodeTreeSanitizer {
   void sanitizeTree(Node node) {}
 }
+
+unbindAll(node) {
+  nodeBind(node).unbindAll();
+  for (var child = node.firstChild; child != null; child = child.nextNode) {
+    unbindAll(child);
+  }
+}