Fix, take 3

pkg/web_components/test/interop_test.dart

 // Copyright (c) 2013, 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 template_wrappers_test;
 
 import 'dart:html';
 import 'dart:async';
 import 'dart:js' show context, JsObject;
 import 'package:unittest/html_config.dart';
 import 'package:unittest/unittest.dart';
 import 'package:web_components/interop.dart';
 import 'package:web_components/polyfill.dart';
 
-main() {
-  useHtmlConfiguration();
-  setUp(() => customElementsReady.then((_) {
+final globalSetup = customElementsReady.then((_) {
     registerDartType('x-a', XAWrapper);
     registerDartType('x-b', XBWrapper, extendsTag: 'div');
     registerDartType('x-c', XCWrapper);
-  }));
+  });
+
+main() {
+  useHtmlConfiguration();
+  setUp(() => globalSetup);
 
   test('interop is supported', () {
     expect(isSupported, isTrue);
   });
 
   test('previously created elements are not upgraded', () {
     var a = document.querySelector('x-a');
     expect(a is HtmlElement, isTrue, reason: 'x-a is HtmlElement');
     expect(a is XAWrapper, isFalse, reason: 'x-a should not be upgraded yet');
     expect(_readX(a), 0);
@@ skipping 64 matching lines @@
   XAWrapper.created() : super.created();
 }
 
 class XBWrapper extends DivElement with Wrapper {
   XBWrapper.created() : super.created();
 }
 
 class XCWrapper extends HtmlElement with Wrapper {
   XCWrapper.created() : super.created();
 }