Material light and dark themes for Sky widgets

sky/examples/widgets/styled_text.dart

Index: sky/examples/widgets/styled_text.dart
diff --git a/sky/examples/widgets/styled_text.dart b/sky/examples/widgets/styled_text.dart
index 6ca309fe4a19896b49c5668a4d5669cb29c1354b..02ba7c3c8fa5fae0eb46ab51990415aa01a785f8 100644
--- a/sky/examples/widgets/styled_text.dart
+++ b/sky/examples/widgets/styled_text.dart
@@ -108,11 +108,11 @@ HAL: This mission is too important for me to allow you to jeopardize it.''';
     );
 
     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')
         )
       )
     );