Fix data loading in the stocks app

sky/sdk/lib/framework/net/image_cache.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';
-import 'dart:collection';
-import 'fetch.dart';
-import 'package:mojom/mojo/url_response.mojom.dart';
-
-final HashMap<String, List<ImageDecoderCallback>> _pendingRequests =
-  new HashMap<String, List<ImageDecoderCallback>>();
-
-final HashMap<String, Image> _completedRequests =
-  new HashMap<String, Image>();
-
-void _loadComplete(url, image) {
-  _completedRequests[url] = image;
-  _pendingRequests[url].forEach((c) => c(image));
-  _pendingRequests.remove(url);
-}
-
-void load(String url, ImageDecoderCallback callback) {
-  Image result = _completedRequests[url];
-  if (result != null) {
-    callback(_completedRequests[url]);
-    return;
-  }
-
-  bool newRequest = false;
-  _pendingRequests.putIfAbsent(url, () {
-    newRequest = true;
-    return new List<ImageDecoderCallback>();
-  }).add(callback);
-  if (newRequest) {
-    fetchUrl(url).then((UrlResponse response) {
-      if (response.statusCode >= 400) {
-        _loadComplete(url, null);
-        return;
-      }
-      new ImageDecoder(response.body.handle.h,
-          (image) => _loadComplete(url, image));
-    });
-  }
-}