Fix after bad merge.

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index 15a55622ccccf2fc0837e3b1684286dd0e75c0a7..6ce15f69bc9ce6f39d26a39138dcae473bbd4370 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -8943,7 +8943,7 @@ class _ChildrenElementList implements List {
       throw new RangeError.range(index, 0, length);
     }
     if (index == length) {
-      _element.$dom_appendChild(element);
+      _element.append(element);
     } else {
       throw new UnimplementedError("insert on ElementLists");
     }
@@ -18886,7 +18886,7 @@ class _ChildNodeListLazy implements List {
       throw new RangeError.range(index, 0, length);
     }
     if (index == length) {
-      _this.$dom_appendChild(node);
+      _this.append(node);
     } else {
       this_.insertBefore(node, this[index]);
     }