Start cleaning up the HTML tests.

pkg/dev_compiler/test/codegen/lib/html/cross_frame_test.dart

Index: pkg/dev_compiler/test/codegen/lib/html/cross_frame_test.dart
diff --git a/pkg/dev_compiler/test/codegen/lib/html/cross_frame_test.dart b/pkg/dev_compiler/test/codegen/lib/html/cross_frame_test.dart
index b5a37f6c3672fe709cb3a513024b4742c77a15ea..6ef77cf35cace614f3e8be07176a9fa44efdb7c2 100644
--- a/pkg/dev_compiler/test/codegen/lib/html/cross_frame_test.dart
+++ b/pkg/dev_compiler/test/codegen/lib/html/cross_frame_test.dart
@@ -1,11 +1,8 @@
-library CrossFrameTest;
-import 'package:unittest/unittest.dart';
-import 'package:unittest/html_config.dart';
 import 'dart:html';
 
-main() {
-  useHtmlConfiguration();
+import 'package:minitest/minitest.dart';
 
+main() {
   var isWindowBase = predicate((x) => x is WindowBase, 'is a WindowBase');
   var isWindow = predicate((x) => x is Window, 'is a Window');
   var isLocationBase = predicate((x) => x is LocationBase, 'is a LocationBase');
@@ -14,7 +11,7 @@ main() {
   var isHistoryBase = predicate((x) => x is HistoryBase, 'is a HistoryBase');
   var isHistory = predicate((x) => x is History, 'is a History');
 
-  final iframe = new Element.tag('iframe');
+  final iframe = new IFrameElement();

[Jacob, 2016/10/12 22:38:31]

why did this line change? Both new Element.tag and new IFrameElement() should
work.

[Bob Nystrom, 2016/10/13 00:12:12]

Strong mode doesn't do the magical type propagation that analyzer does for new
Element.tag(), and the hope is to remove it for 2.0.

   document.body.append(iframe);
 
   test('window', () {