Add List.reversed to give a reverse fixed-length view of a list.

sdk/lib/html/html_common/filtered_element_list.dart

Index: sdk/lib/html/html_common/filtered_element_list.dart
diff --git a/sdk/lib/html/html_common/filtered_element_list.dart b/sdk/lib/html/html_common/filtered_element_list.dart
index 1c76f00ba8bf41279716fd860332085de9a380c5..a9cce44413ab449d919d18bd28aabc83c0d60a87 100644
--- a/sdk/lib/html/html_common/filtered_element_list.dart
+++ b/sdk/lib/html/html_common/filtered_element_list.dart
@@ -69,6 +69,8 @@ class FilteredElementList implements List {
     return element is Element && _childNodes.contains(element);
   }
 
+  List<E> get reversed => new ReversedListView<E>(_filtered, 0, null);
+
   void sort([int compare(Element a, Element b)]) {
     throw new UnsupportedError('TODO(jacobr): should we impl?');
   }