Teach Stocks how to load data when run from a package

sky/sdk/example/stocks/lib/stock_data.dart

 // Copyright 2014 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:convert';
 import 'dart:math';
 
 import 'package:sky/mojo/net/fetch.dart';
+import 'package:sky/mojo/asset_bundle.dart';
 
 // Snapshot from http://www.nasdaq.com/screening/company-list.aspx
 // Fetched 2/23/2014.
 // "Symbol","Name","LastSale","MarketCap","IPOyear","Sector","industry","Summary Quote",
 // Data in stock_data.json
 
 final Random _rng = new Random();
 
 class Stock {
   String symbol;
@@ skipping 25 matching lines @@
 
   void appendTo(List<Stock> stocks) {
     for (List<String> fields in _data)
       stocks.add(new Stock.fromFields(fields));
   }
 }
 
 typedef void StockDataCallback(StockData data);
 const _kChunkCount = 30;
 
+String _urlToFetch(int chunk) {
+  if (rootBundle == null)
+    return '../data/stock_data_${chunk}.json';
+  return 'https://domokit.github.io/example/stocks/data/stock_data_${chunk}.json';
+}
+
 class StockDataFetcher {
   int _currentChunk = 0;
   final StockDataCallback callback;
 
   StockDataFetcher(this.callback) {
     _fetchNextChunk();
   }
 
   void _fetchNextChunk() {
-    fetchBody('../data/stock_data_${_currentChunk++}.json').then((Response response) {
+    fetchBody(_urlToFetch(_currentChunk++)).then((Response response) {
       String json = response.bodyAsString();
       JsonDecoder decoder = new JsonDecoder();
 
       callback(new StockData(decoder.convert(json)));
 
       if (_currentChunk < _kChunkCount)
         _fetchNextChunk();
     });
   }
 }