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

sky/examples/stocks2/lib/stock_list.dart

Index: sky/examples/stocks2/lib/stock_list.dart
diff --git a/sky/examples/stocks2/lib/stock_list.dart b/sky/examples/stocks2/lib/stock_list.dart
index 58fa601ba9decca16f4fbf7f092a487241381fcc..7ff6fe8cb75f4d4809cee722c800992885b3fa7f 100644
--- a/sky/examples/stocks2/lib/stock_list.dart
+++ b/sky/examples/stocks2/lib/stock_list.dart
@@ -8,8 +8,6 @@ import 'stock_data.dart';
 import 'stock_row.dart';
 
 class Stocklist extends FixedHeightScrollable {
-  String query;
-  List<Stock> stocks;
 
   Stocklist({
     Object key,
@@ -17,6 +15,15 @@ class Stocklist extends FixedHeightScrollable {
     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 ||