Add List.insert.

tools/dom/templates/html/impl/impl_Element.darttemplate

Index: tools/dom/templates/html/impl/impl_Element.darttemplate
diff --git a/tools/dom/templates/html/impl/impl_Element.darttemplate b/tools/dom/templates/html/impl/impl_Element.darttemplate
index 35e8e2ffc9c4241e892495858b71b43fe1e7887d..999134d93c43f1e710febc81a6533e16710c8bd3 100644
--- a/tools/dom/templates/html/impl/impl_Element.darttemplate
+++ b/tools/dom/templates/html/impl/impl_Element.darttemplate
@@ -214,6 +214,15 @@ class _ChildrenElementList implements List {
     return Lists.lastIndexOf(this, element, start);
   }
 
+  void insert(int index, Element element) {
+    if (index < 0 || index > length) throw RangeError(index);
+    if (index == length) {
+      _element.$dom_appendChild(element);
+    } else {
+      throw new UnimplementedError("insert on ElementLists");

[Lasse Reichstein Nielsen, 2013/03/07 09:57:53]

Can you use:
 _element.$dom_insertBefore(element, _childElements[index]);
?

[floitsch, 2013/03/07 12:53:53]

No. doesn't exist in Dart yet. That's why I added Pete as reviewer.

[blois, 2013/03/08 02:32:40]

I would leave this as unsupported for now. I can investigate  implementing.
insertBefore doesn't quite fit as it deals with nodes which are a superset of
elements.

+    }
+  }
+
   void clear() {
     // It is unclear if we want to keep non element nodes?
     _element.text = '';