Add material shadows to toolbar and drawer

sky/sdk/lib/framework/components2/tool_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 '../fn2.dart';
 import '../theme/view_configuration.dart';
-// import 'material.dart';
+import '../theme2/shadows.dart';
 
 class ToolBar extends Component {
   UINode left;
   UINode center;
   List<UINode> right;
   Color backgroundColor;
 
   ToolBar({
     String key,
     this.left,
@@ skipping 15 matching lines @@
     if (right != null)
       children.addAll(right);
 
     return new Container(
       child: new FlexContainer(
         children: children,
         direction: FlexDirection.horizontal
       ),
       height: 56.0,
       padding: new EdgeDims(kStatusBarHeight.toDouble(), 8.0, 0.0, 8.0),
-      decoration: new BoxDecoration(backgroundColor: backgroundColor)
+      decoration: new BoxDecoration(
+        backgroundColor: backgroundColor,
+        boxShadow: Shadow[2]
+      )
     );
   }
 }