Support for icon theming

sky/sdk/example/fitness/lib/home.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/widgets/basic.dart';
 import 'package:sky/widgets/drawer.dart';
 import 'package:sky/widgets/drawer_header.dart';
 import 'package:sky/widgets/floating_action_button.dart';
 import 'package:sky/widgets/icon.dart';
@@ skipping 98 matching lines @@
   String get fitnessModeTitle {
     switch(_fitnessMode) {
       case FitnessMode.measure: return "Measure";
       case FitnessMode.run: return "Run";
     }
   }
 
   Widget buildToolBar() {
     return new ToolBar(
       left: new IconButton(
-        icon: 'navigation/menu_white',
+        icon: "navigation/menu",
         onPressed: _handleOpenDrawer),
       center: new Text(fitnessModeTitle)
     );
   }
 
   Widget buildBody() {
     TextStyle style = Theme.of(this).text.title;
     switch (_fitnessMode) {
       case FitnessMode.measure:
         return new Material(
@@ skipping 43 matching lines @@
   void _handleRunStopped() {
     setState(() {
       _isRunning = false;
     });
   }
 
   Widget buildFloatingActionButton() {
     switch (_fitnessMode) {
       case FitnessMode.measure:
         return new FloatingActionButton(
-          child: new Icon(type: 'content/add_white', size: 24),
+          child: new Icon(type: 'content/add', size: 24),
           onPressed: _handleMeasurementAdded
         );
       case FitnessMode.run:
         return new FloatingActionButton(
           child: new Icon(
-            type: _isRunning ? 'av/stop_white' : 'maps/directions_run_white',
+            type: _isRunning ? 'av/stop' : 'maps/directions_run',
             size: 24
           ),
           onPressed: _isRunning ? _handleRunStopped : _handleRunStarted
         );
     }
   }
 
   Widget build() {
     return new Scaffold(
       toolbar: buildToolBar(),
       body: buildBody(),
       snackBar: buildSnackBar(),
       floatingActionButton: buildFloatingActionButton(),
       drawer: _drawerShowing ? buildDrawer() : null
     );
   }
 }