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

sky/examples/stocks2/lib/stock_list.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/framework/components2/fixed_height_scrollable.dart';
 import 'package:sky/framework/fn2.dart';
 import 'stock_data.dart';
 import 'stock_row.dart';
 
 class Stocklist extends FixedHeightScrollable {
-  String query;
-  List<Stock> stocks;
 
   Stocklist({
     Object key,
     this.stocks,
     this.query
   }) : super(itemHeight: StockRow.kHeight, key: key);
 
+  String query;
+  List<Stock> stocks;
+
+  void syncFields(Stocklist source) {
+    query = source.query;
+    stocks = source.stocks;
+    super.syncFields(source);
+  }
+
   List<UINode> buildItems(int start, int count) {
     var filteredStocks = stocks.where((stock) {
       return query == null ||
              stock.symbol.contains(new RegExp(query, caseSensitive: false));
     });
     itemCount = filteredStocks.length;
     return filteredStocks
       .skip(start)
       .take(count)
       .map((stock) => new StockRow(stock: stock))
       .toList(growable: false);
   }
 }