[Effen] Convert action_bar.dart to using a FlexContainer.

sky/framework/components/action_bar.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 '../fn.dart';
+import '../layout.dart';
 import '../theme/view_configuration.dart';
 import 'material.dart';
 
 class ActionBar extends Component {
   static final Style _style = new Style('''
-    display: flex;
-    flex-direction: row;
     align-items: center;
     height: 56px;
     padding: 0 8px;
     transition: background-color 0.3s;
     padding-top: ${kStatusBarHeight}px;''');
 
   static Style _centerStyle = new Style('''
     padding-left: 24px;
     flex: 1;''');
 
   UINode left;
   UINode center;
   List<UINode> right;
 
   ActionBar({
     String key,
     this.left,
     this.center,
     this.right
   }) : super(key: key);
 
   UINode build() {
     List<UINode> children = [left, new StyleNode(center, _centerStyle)];
 
     if (right != null)
       children.addAll(right);
 
     return new Material(
-      content: new Container(style: _style, children: children),
+      content: new FlexContainer(
+        style: _style,
+        children: children,
+        direction: FlexDirection.Row),
       level: 2);
   }
 }