Implement manifest icon downloader

chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h

Index: chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
diff --git a/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h b/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
index d3af3ac1c0f8b7198f3d36d439046c2de4646e38..42d72b8fa9f18f15dea4781c33c3f036ed5b1974 100644
--- a/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
+++ b/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
@@ -23,6 +23,7 @@ class Message;
 }
 
 class GURL;
+class ManifestIconDownloader;
 
 // Aysnchronously fetches and processes data needed to create a shortcut for an
 // Android Home screen launcher.
@@ -82,13 +83,9 @@ class AddToHomescreenDataFetcher
   void CreateLauncherIcon(
       const favicon_base::FaviconRawBitmapResult& bitmap_result);
 
-  // Callback run after an attempt to download manifest icon has been made.  May
-  // kick off the download of a favicon if it failed.
-  void OnManifestIconFetched(int id,
-                             int http_status_code,
-                             const GURL& url,
-                             const std::vector<SkBitmap>& bitmaps,
-                             const std::vector<gfx::Size>& sizes);
+  // Callback run after an attempt to download manifest icon has been made. May
+  // kick off the download of a favicon if it failed (i.e. the bitmap is empty).
+  void OnManifestIconFetched(const SkBitmap& icon);
 
   // Notifies the observer that the shortcut data is all available.
   void NotifyObserver(const SkBitmap& icon);
@@ -105,6 +102,8 @@ class AddToHomescreenDataFetcher
   SkBitmap shortcut_icon_;
   base::CancelableTaskTracker favicon_task_tracker_;
 
+  scoped_ptr<ManifestIconDownloader> icon_downloader_;
+
   const int preferred_icon_size_in_px_;
   static const int kPreferredIconSizeInDp;