Fixing SelectElement.options, adding support for optgroup.

tests/html/selectelement_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library selectelement_test;
 import '../../pkg/unittest/lib/unittest.dart';
 import '../../pkg/unittest/lib/html_config.dart';
 import 'dart:html';
 
 main() {
@@ skipping 37 matching lines @@
     var options = [
       new OptionElement(),
       new OptionElement('data', 'two', false, true),
       new OptionElement('data', 'two', false, true),
       new OptionElement(),
     ];
     element.children.addAll(options);
     // Use last to make sure that the list was correctly wrapped.
     expect(element.options.last, equals(options[3]));
   });
+
+  test('optgroup', () {
+    var element = new SelectElement();
+    element.innerHtml =
+        '<option>1</option>'
+        '<optgroup>'
+          '<option>2</option>'
+        '</optgroup>';
+
+    expect(element.options.length, 2);
+    element.selectedIndex = 1;
+
+    var optGroup = element.children[1];
+    expect(optGroup is OptGroupElement, isTrue);
+    expect(optGroup.children.single.selected, isTrue);
+    expect(element.selectedOptions, optGroup.children);
+  });
 }