Handle app custom icon via aura::Window property.

chrome/browser/ui/ash/launcher/arc_app_deferred_launcher_controller.h

 // Copyright 2016 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_UI_ASH_LAUNCHER_ARC_APP_DEFERRED_LAUNCHER_CONTROLLER_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_DEFERRED_LAUNCHER_CONTROLLER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 44 matching lines @@
   // and removes entry from the list of tracking items.
   void Close(const std::string& app_id);
 
  private:
   // Defines mapping of a shelf app id to a corresponded controller. Shelf app
   // id is optional mapping (for example, Play Store to ARC Host Support).
   using AppControllerMap =
       std::map<std::string, ArcAppDeferredLauncherItemController*>;
 
   void UpdateApps();
-  void UpdateApp(const std::string& app_id);
+  void UpdateShelfItemIcon(const std::string& app_id);
   void RegisterNextUpdate();
 
   // Unowned pointers.
   ChromeLauncherController* owner_;
   Profile* observed_profile_ = nullptr;
 
   AppControllerMap app_controller_map_;
 
   // Always keep this the last member of this class.
   base::WeakPtrFactory<ArcAppDeferredLauncherController> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcAppDeferredLauncherController);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_DEFERRED_LAUNCHER_CONTROLLER_H_