Fix stocks app test

sky/examples/stocks2/lib/stock_app.dart

Index: sky/examples/stocks2/lib/stock_app.dart
diff --git a/sky/examples/stocks2/lib/stock_app.dart b/sky/examples/stocks2/lib/stock_app.dart
index b88d5f806405bab02bdb689d2c3fc8b9f00f2828..1c450b02682fb75f735bc53d954cc653f201783e 100644
--- a/sky/examples/stocks2/lib/stock_app.dart
+++ b/sky/examples/stocks2/lib/stock_app.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:sky/rendering/box.dart';
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/navigator.dart';
 import 'package:sky/widgets/widget.dart';
@@ -10,6 +11,9 @@ import 'stock_home.dart';
 import 'stock_settings.dart';
 
 class StocksApp extends App {
+
+  StocksApp({ RenderView renderViewOverride }) : super(renderViewOverride: renderViewOverride);
+
   Widget build() {
     return new Navigator(
       routes: [