Material light and dark themes for Sky widgets

sky/examples/widgets/styled_text.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/painting/text_style.dart';
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/flex.dart';
 import 'package:sky/rendering/sky_binding.dart';
 import 'package:sky/theme/colors.dart';
 import 'package:sky/theme/theme_data.dart';
@@ skipping 90 matching lines @@
           alignItems: FlexAlignItems.flexStart
         )
       );
 
     Listener interactiveBody = new Listener(
       child: body,
       onPointerDown: toggleToTextFunction
     );
 
     return new Theme(
-      data: new ThemeData(color: Blue, text: white),
+      data: new ThemeData.dark(primary: Red),
       child: new Scaffold(
         body: new Material(child: interactiveBody),
         toolbar: new ToolBar(
-          center: new Text('Hal and Dave', style: white.title)
+          center: new Text('Hal and Dave')
         )
       )
     );
   }
 }
 
 void main() {
   runApp(new StyledTextApp());
   SkyBinding.instance.onFrame = () {
     // uncomment this for debugging:
     // SkyBinding.instance.debugDumpRenderTree();
   };
 }