Make RenderParagraph mutable, and make it fit the new RenderNode protocols

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 '../layout2.dart';
 import '../theme/view_configuration.dart';
 import 'material.dart';
 
 class ToolBar extends Component {
@@ skipping 21 matching lines @@
   }) : super(key: key);
 
   UINode build() {
     List<UINode> children = [left, new StyleNode(new ParentDataNode(center, _centerLayoutSettings), _centerStyle)];
 
     if (right != null)
       children.addAll(right);
 
     return new Material(
       content: new FlexContainer(
-        style: _style,
         children: children,
         direction: FlexDirection.Row),
       level: 2);
   }
 }