Use sky_shell instead of mojo_shell for testing.

sky/tests/resources/display_list.dart

 
 import 'dart:async';
 import 'dart:sky' as sky;
-import "dart:sky.internals" as internals;
 import 'dart:typed_data';
 
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/object.dart';
 
+import 'harness.dart';
+
 typedef void Logger (String s);
 
 class TestPaintingCanvas extends PaintingCanvas {
   TestPaintingCanvas(sky.PictureRecorder recorder, Size size, this.logger, { this.indent: '' })
     : size = size,
       super(recorder, size) {
     log("TestPaintingCanvas() constructor: ${size.width} x ${size.height}");
   }
 
   final String indent;
@@ skipping 130 matching lines @@
     RenderObject.flushLayout();
     paintFrame();
     print(lastPaint); // TODO(ianh): figure out how to make this fit the unit testing framework better
   }
 
   Future checkFrame() {
     return new Future.microtask(syncCheckFrame);
   }
 
   void endTest() {
-    internals.notifyTestComplete("PAINTED $frame FRAMES");
+    notifyTestComplete("PAINTED $frame FRAMES");
   }
 
 }
 
 class TestApp extends App {
   TestApp({ this.builder });
 
   Function builder;
 
   Widget build() {
     return builder();
   }
 }
 
 class WidgetTester {
   TestRenderView renderView = new TestRenderView();
 
   Future test(Function builder) {
     runApp(new TestApp(builder: builder), renderViewOverride: renderView);
     return renderView.checkFrame();
   }
 
   void endTest() {
     renderView.endTest();
   }
 }