Fix a data race on the ref count of AddToHomescreenDataFetcher

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/callback_forward.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "base/timer/timer.h"
 #include "chrome/browser/android/shortcut_info.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
+namespace base {
+class TaskRunner;
+}
+
 namespace content {
 class WebContents;
 }
 
 namespace favicon_base {
 struct FaviconRawBitmapResult;
 }
 
 namespace IPC {
 class Message;
@@ skipping 80 matching lines @@
   void OnDidPerformInstallableCheck(const InstallableData& data);
 
   // 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. shortcut_info_.url is
   // used to generate an icon if there is no bitmap in |bitmap_result| or the
   // bitmap is not large enough.
-  void CreateLauncherIconFromFaviconInBackground(
+  SkBitmap CreateLauncherIconFromFaviconInBackground(
       const favicon_base::FaviconRawBitmapResult& bitmap_result);
 
   // Creates the launcher icon from the given |raw_icon|.
   void CreateLauncherIcon(const SkBitmap& raw_icon);
-  void CreateLauncherIconInBackground(const SkBitmap& raw_icon);
+  SkBitmap CreateLauncherIconInBackground(const SkBitmap& raw_icon);
 
   // Notifies the observer that the shortcut data is all available.
   void NotifyObserver(const SkBitmap& icon);
 
+  scoped_refptr<base::TaskRunner> background_task_runner_;
+
   Observer* weak_observer_;
 
   // The icons must only be set on the UI thread for thread safety.
   SkBitmap badge_icon_;
   SkBitmap primary_icon_;
   ShortcutInfo shortcut_info_;
   GURL splash_screen_url_;
 
   base::CancelableTaskTracker favicon_task_tracker_;
   base::Timer data_timeout_timer_;
 
   const int ideal_icon_size_in_px_;
   const int minimum_icon_size_in_px_;
   const int ideal_splash_image_size_in_px_;
   const int minimum_splash_image_size_in_px_;
   const int badge_size_in_px_;
 
   // Indicates whether to check WebAPK compatibility.
   bool check_webapk_compatibility_;
   bool is_waiting_for_web_application_info_;
   bool is_installable_check_complete_;
   bool is_icon_saved_;
   bool is_ready_;
 
   DISALLOW_COPY_AND_ASSIGN(AddToHomescreenDataFetcher);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_WEBAPPS_ADD_TO_HOMESCREEN_DATA_FETCHER_H_