Clean up the tests to be more maintainable.

sky/tests/widgets/syncs1.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:async';
 
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/raised_button.dart';
 
 import '../resources/display_list.dart';
@@ skipping 63 matching lines @@
       ),
       new SizedBox(
         key: 'stack-example',
         height: 250.0,
         child: arbitrarySetting ? buildStack1() : buildStack2()
       )
     ]);
   }
 }
 
-main() {
+main() async {
   TestRenderView renderViewOverride = new TestRenderView();
   FiddleApp app = new FiddleApp();
   runApp(app, renderViewOverride: renderViewOverride);
-  new Future.microtask(() {
-    renderViewOverride.checkFrame();
-    app.toggle();
-    new Future.microtask(() {
-      renderViewOverride.checkFrame();
-      app.toggle();
-      new Future.microtask(() {
-        renderViewOverride.checkFrame();
-        renderViewOverride.endTest();
-      });
-    });
-  });
+  await renderViewOverride.checkFrame();
+  app.toggle();
+  await renderViewOverride.checkFrame();
+  app.toggle();
+  await renderViewOverride.checkFrame();
+  renderViewOverride.endTest();
 }