Port sky_home to the new SkyView world

sky/examples/rendering/transform.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:sky' as sky;
 import 'package:sky/framework/app.dart';
 import 'package:sky/framework/rendering/flex.dart';
 import 'package:sky/framework/rendering/box.dart';
 import 'package:vector_math/vector_math.dart';
 
 AppView app;
 
 void main() {
   RenderDecoratedBox green = new RenderDecoratedBox(
       decoration: new BoxDecoration(backgroundColor: const sky.Color(0xFF00FF00)));
   RenderSizedBox box = new RenderSizedBox(
       desiredSize: new sky.Size(200.0, 200.0), child: green);
 
   Matrix4 transform = new Matrix4.identity();
   RenderTransform spin = new RenderTransform(
       transform: transform, child: box);
   spin.rotateZ(1.0);
 
   RenderFlex flex = new RenderFlex();
   flex.add(spin);
-  app = new AppView(flex);
+  app = new AppView(root: flex);
 }