Fix Asteroids game to paint again and give it an icon.

sky/sdk/example/game/main.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 'package:sky/mojo/activity.dart' as activity;
 import 'package:sky/mojo/asset_bundle.dart';
+import 'package:sky/theme/colors.dart' as colors;
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/widget.dart';
 
 import 'lib/game_demo.dart';
 import 'lib/sprites.dart';
 
 AssetBundle _initBundle() {
   if (rootBundle != null)
     return rootBundle;
   return new NetworkAssetBundle(Uri.base);
@@ skipping 11 matching lines @@
   await _loader.load([
     'assets/nebula.png',
     'assets/sprites.png',
     'assets/starfield.png',
   ]);
 
   String json = await _bundle.loadString('assets/sprites.json');
   _spriteSheet = new SpriteSheet(_loader['assets/sprites.png'], json);
   _app = new GameDemoApp();
 
+  // TODO(viktork): This task bar color is the wrong purple.
+  activity.updateTaskDescription('Asteroids', colors.Purple[500]);

[abarth-chromium, 2015/07/10 20:24:54]

Why not use a widget in the GameDemoApp?

   runApp(_app);
 }
 
 class GameDemoApp extends App {
 
   Widget build() {
     return new Stack([
       new SpriteWidget(new GameDemoWorld(_app, _loader, _spriteSheet)),
 //      new StackPositionedChild(
 //        new Flex([
 //          new FlexExpandingChild(
 //            new RaisedButton(child:new Text("Hello")),
 //            key: 1
 //          ),
 //          new FlexExpandingChild(
 //            new RaisedButton(child:new Text("Foo!")),
 //            key: 2
 //          )
 //        ]),
 //        right:0.0,
 //        top: 20.0
 //      )
     ]);
   }
 }
 
 void resetGame() {
   _app.scheduleBuild();
 }