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 6b75c1324416915a1c09353e648e2bc68bada7ea..c3e5c9b8c8d8fed2131ffde0d5b4198c14fd40cf 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 insertAt(int index, Element element) {
+    if (index < 0 || index > length) throw RangeError(index);
+    if (index == length) {
+      _element.$dom_appendChild(element);
+    } else {
+      throw new UnimplementedError("insertAt on ElementLists");

[sra1, 2013/03/08 18:56:53]

insertBefore the current element at that slot?

[floitsch, 2013/03/08 23:17:30]

Pete told me to keep it unimplemented: "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 = '';