Use Theme to define the colors and TextStyles for Tab, TabBar

sky/examples/widgets/tabs.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/theme/colors.dart';
 import 'package:sky/theme/typography.dart';
 import 'package:sky/widgets/basic.dart';
 import 'package:sky/widgets/material.dart';
 import 'package:sky/widgets/scaffold.dart';
 import 'package:sky/widgets/tabs.dart';
@@ skipping 26 matching lines @@
       .map((s) => new TabLabel(icon: 'action/search_white'));
 
     Iterable<TabLabel> textAndIconLabels = items
       .map((s) => new TabLabel(text: "ITEM " + s, icon: 'action/search_white'));
 
     var navigatorIndex = 0;
     Iterable<Widget> tabNavigators = [textLabels, iconLabels, textAndIconLabels]
       .map((labels) => buildTabNavigator(labels, navigatorIndex++));
 
     ToolBar toolbar = new ToolBar(
-      center: new Text('Tabbed Navigator', style: white.title),
-      backgroundColor: Blue[500]);
+      center: new Text('Tabbed Navigator', style: white.title)
+    );
 
     return new Scaffold(
       toolbar: toolbar,
       body: new Material(
         child: new Center(child: new Block(tabNavigators.toList())),
         color: Grey[500]
       )
     );
   }
 }
 
 void main() {
   runApp(new TabbedNavigatorApp());
 }