Fixing SelectElement.options, adding support for optgroup.

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 f5a4b1a199cb20ce0631965f750924e977921399..a12834b5ce287a16226f6a834fcba85be242df51 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -20204,7 +20204,8 @@ class SelectElement extends _Element_Merged {
   // 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);
   }