Handle app custom icon via aura::Window property.

chrome/browser/ui/ash/launcher/extension_app_window_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_EXTENSION_APP_WINDOW_LAUNCHER_CONTROLLER_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_EXTENSION_APP_WINDOW_LAUNCHER_CONTROLLER_H_
 
 #include <list>
 #include <map>
 #include <string>
@@ skipping 27 matching lines @@
   explicit ExtensionAppWindowLauncherController(
       ChromeLauncherController* owner);
   ~ExtensionAppWindowLauncherController() override;
 
   // AppWindowLauncherController:
   void AdditionalUserAddedToSession(Profile* profile) override;
   AppWindowLauncherItemController* ControllerForWindow(
       aura::Window* window) override;
 
   // Overridden from AppWindowRegistry::Observer:
-  void OnAppWindowIconChanged(extensions::AppWindow* app_window) override;
   void OnAppWindowShown(extensions::AppWindow* app_window,
                         bool was_hidden) override;
   void OnAppWindowHidden(extensions::AppWindow* app_window) override;
 
   // Overriden from aura::WindowObserver:
   void OnWindowDestroying(aura::Window* window) override;
 
  protected:
   // Registers a app window with the shelf and this object.
   void RegisterApp(extensions::AppWindow* app_window);
@@ skipping 16 matching lines @@
   // Map of shelf id to controller.
   AppControllerMap app_controller_map_;
 
   // Map of aura::Windows to shelf ids.
   std::map<aura::Window*, ash::ShelfID> window_to_shelf_id_map_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionAppWindowLauncherController);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_EXTENSION_APP_WINDOW_LAUNCHER_CONTROLLER_H_