Implement manifest icon downloader

chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_WEBAPPS_ADD_TO_HOMESCREEN_DATA_FETCHER_H_
 #define CHROME_BROWSER_ANDROID_WEBAPPS_ADD_TO_HOMESCREEN_DATA_FETCHER_H_
 
 #include "base/basictypes.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "base/timer/timer.h"
@@ skipping 64 matching lines @@
 
   // Grabs the favicon for the current URL.
   void FetchFavicon();
   void OnFaviconFetched(
       const favicon_base::FaviconRawBitmapResult& bitmap_result);
 
   // Creates the launcher icon from the given bitmap.
   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);
 
   Observer* weak_observer_;
 
   bool is_waiting_for_web_application_info_;
   bool is_icon_saved_;
   bool is_ready_;
   base::Timer icon_timeout_timer_;
   ShortcutInfo shortcut_info_;
 
   // The icon must only be set on the UI thread for thread safety.
   SkBitmap shortcut_icon_;
   base::CancelableTaskTracker favicon_task_tracker_;
 
   const int preferred_icon_size_in_px_;
   static const int kPreferredIconSizeInDp;
 
   friend class base::RefCounted<AddToHomescreenDataFetcher>;
   DISALLOW_COPY_AND_ASSIGN(AddToHomescreenDataFetcher);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_WEBAPPS_ADD_TO_HOMESCREEN_DATA_FETCHER_H_