Start cleaning up the HTML tests.

pkg/dev_compiler/test/codegen/lib/html/datalistelement_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 datalistelement_dataview_test;
-import 'package:unittest/unittest.dart';
-import 'package:unittest/html_config.dart';
 import 'dart:html';
 
+import 'package:minitest/minitest.dart';
+
 main() {
-  useHtmlConfiguration();
-
   var isDataListElement =
       predicate((x) => x is DataListElement, 'is a DataListElement');
 
   var div;
 
   setUp(() {
       div = new DivElement();
       document.body.append(div);
       div.innerHtml = """
 <input id="input" list="browsers" />
@@ skipping 16 matching lines @@
 
   test('is', () {
     expect(() {
       var list = document.query('#browsers');
       expect(list, isDataListElement);
     }, expectation);
   });
 
   test('list', () {
     expect(() {
-      var list = document.query('#browsers');
-      var input = document.query('#input');
+      var list = document.query('#browsers') as DataListElement;
+      var input = document.query('#input') as InputElement;
       expect(input.list, list);
     }, expectation);
   });
 
   test('options', () {
     expect(() {
-      var options = document.query('#browsers').options;
+      var options = (document.query('#browsers') as DataListElement).options;
       expect(options.length, 5);
     }, expectation);
   });
 
   test('create', () {
     expect(() {
       var list = new DataListElement();
       expect(list, isDataListElement);
     }, expectation);
   });
 }