Remove one more use of mirrors: Components now have to explicitly sync their fields.

sky/examples/stocks2/lib/stock_row.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 'dart:sky' as sky;
 import 'package:sky/framework/components2/ink_well.dart';
 import 'package:sky/framework/fn2.dart';
 import 'package:sky/framework/rendering/flex.dart';
 import 'package:sky/framework/rendering/box.dart';
 import 'package:sky/framework/theme/typography.dart' as typography;
 import 'stock_arrow.dart';
 import 'stock_data.dart';
 
 class StockRow extends Component {
-  static const double kHeight = 70.0;
+
+  StockRow({ this.stock }) : super(key: stock.symbol);
 
   Stock stock;
 
-  StockRow({ Stock stock }) : super(key: stock.symbol) {
-    this.stock = stock;
+  void syncFields(StockRow source) {
+    stock = source.stock;
+    super.syncFields(source);
   }
 
+  static const double kHeight = 70.0;
+
   UINode build() {
     String lastSale = "\$${stock.lastSale.toStringAsFixed(2)}";
 
     String changeInPrice = "${stock.percentChange.toStringAsFixed(2)}%";
     if (stock.percentChange > 0) changeInPrice = "+" + changeInPrice;
 
     List<UINode> children = [
       new Container(
           child: new StockArrow(percentChange: stock.percentChange),
           margin: const EdgeDims.only(right: 5.0)),
       new FlexExpandingChild(new Text(stock.symbol), flex: 2, key: "symbol"),
       // TODO(hansmuller): text-align: right
       new FlexExpandingChild(new Text(lastSale), key: "lastSale"),
       // TODO(hansmuller): text-align: right, ${typography.black.caption};
       new FlexExpandingChild(new Text(changeInPrice), key: "changeInPrice")
     ];
 
     return new Container(
       padding: const EdgeDims(16.0, 16.0, 20.0, 16.0),
       height: kHeight, // TODO(hansmuller): This shouldn't be needed
       decoration: const BoxDecoration(
           backgroundColor: const sky.Color(0xFFFFFFFF),
           border: const Border(
               bottom: const BorderSide(
                   color: const sky.Color(0xFFF4F4F4),
                   width: 1.0))),
       child: new FlexContainer(children: children));
   }
 }