Calls ShortcutHelper::FinalizeLauncherIcon() on worker thread instead of on IO thread

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 d02b94576e07aa3f981ee13c89db80f71d8d2554..55ca890e9bbbbbb2b71ae79befa13e2c7b9e7348 100644
--- a/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
+++ b/chrome/browser/android/webapps/add_to_homescreen_data_fetcher.h
@@ -44,9 +44,9 @@ class AddToHomescreenDataFetcher
     // Converts the icon into one that can be used on the Android Home screen.
     // |is_generated| is an out-param that indicates whether the icon was
     // generated by Chrome.
-    virtual SkBitmap FinalizeLauncherIcon(const SkBitmap& icon,
-                                          const GURL& url,
-                                          bool* is_generated) = 0;
+    virtual SkBitmap FinalizeLauncherIconInBackground(const SkBitmap& icon,
+                                                      const GURL& url,
+                                                      bool* is_generated) = 0;
 
     // Called when all the data needed to create a shortcut is available.
     virtual void OnDataAvailable(const ShortcutInfo& info,
@@ -91,8 +91,11 @@ class AddToHomescreenDataFetcher
   void OnFaviconFetched(
       const favicon_base::FaviconRawBitmapResult& bitmap_result);
 
-  // Creates the launcher icon from the given bitmap.
-  void CreateLauncherIcon(
+  // Creates the launcher icon from the given bitmap and page URL. The page URL
+  // is used to generate an icon if there is no bitmap in |bitmap_result| or the
+  // bitmap is not large enough.
+  void CreateLauncherIconInBackground(
+      const GURL& page_url,
       const favicon_base::FaviconRawBitmapResult& bitmap_result);
 
   // Callback run after an attempt to download manifest icon has been made. May
@@ -100,7 +103,7 @@ class AddToHomescreenDataFetcher
   void OnManifestIconFetched(const GURL& icon_url, const SkBitmap& icon);
 
   // Notifies the observer that the shortcut data is all available.
-  void NotifyObserver(const SkBitmap& icon);
+  void NotifyObserver(const GURL& icon_url, const SkBitmap& icon);
 
   // Looks up the original, online URL of the site requested.  The URL from the
   // WebContents may be an offline page or a distilled article which is not