Fix resource clean up in TemplateIterator.close()

sky/framework/sky-element/sky-binder.sky

 <!--
 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 -->
 <import src="observe.sky" as="observe" />
 
 <script>
 var stagingDocument = new Document();
 
@@ skipping 437 matching lines @@
   close() {
     if (this.closed)
       return;
     this.unobserve();
     for (var i = 0; i < this.instances.length; i++) {
       this.instances[i].close();
     }
 
     this.instances.length = 0;
 
-    if (this.ifBinding)
-      this.ifBinding.close();
-    if (this.binding)
-      this.binding.close();
+    if (this.ifObserver)
+      this.ifObserver.close();
+    if (this.valueObserver)
+      this.valueObserver.close();
 
     iterators.delete(this.template);
     this.closed = true;
   }
 }
 
 module.exports = {
   createInstance: createInstance,
 };
 </script>