sdk/lib/html/dart2js/html_dart2js.dart

Index: sdk/lib/html/dart2js/html_dart2js.dart
diff --git a/sdk/lib/html/dart2js/html_dart2js.dart b/sdk/lib/html/dart2js/html_dart2js.dart
index cbf24a1339b732208523ca1c0cfd9b61e6d1e7bb..0d019a93dedd8ba40f9a480e778ae30f4d4d7bdd 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -8156,6 +8156,10 @@ class _ChildrenElementList implements List {
   Iterator<Element> get iterator => toList().iterator;
 
   void addAll(Iterable<Element> iterable) {
+    if (iterable is _ChildNodeListLazy) {
+      iterable = new List.from(iterable);
+    }
+
     for (Element element in iterable) {
       _element.$dom_appendChild(element);
     }
@@ -17028,6 +17032,9 @@ class _ChildNodeListLazy implements List {
 
 
   void addAll(Iterable<Node> iterable) {
+    if (iterable is _ChildNodeListLazy) {
+      iterable = new List.from(iterable);
+    }
     for (Node node in iterable) {
       _this.$dom_appendChild(node);
     }