Fixing SelectElement.options, adding support for optgroup.

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 ea38b93dfe008a3c2fc6e7a3dad8c14f72107311..b8958a97d611d00622012ca80bd68512da8878fd 100644
--- a/sdk/lib/html/dart2js/html_dart2js.dart
+++ b/sdk/lib/html/dart2js/html_dart2js.dart
@@ -18884,7 +18884,8 @@ class SelectElement extends Element native "HTMLSelectElement" {
   // Override default options, since IE returns SelectElement itself and it
   // does not operate as a List.
   List<OptionElement> get options {
-    var options = this.children.where((e) => e is OptionElement).toList();
+    var options =
+        this.queryAll('option').where((e) => e is OptionElement).toList();
     return new UnmodifiableListView(options);
   }