Use Ash's ShelfWindowWatcher for app panel windows.

chrome/browser/ui/ash/launcher/extension_app_window_launcher_item_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_ITEM_CONTROLLER_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_EXTENSION_APP_WINDOW_LAUNCHER_ITEM_CONTROLLER_H_
 
 #include <map>
 #include <string>
 
@@ skipping 16 matching lines @@
       ChromeLauncherController* controller);
 
   ~ExtensionAppWindowLauncherItemController() override;
 
   void AddAppWindow(extensions::AppWindow* app_window);
 
   // LauncherItemController overrides:
   ChromeLauncherAppMenuItems GetApplicationList(int event_flags) override;
   ash::ShelfItemDelegate::PerformedAction ItemSelected(
       const ui::Event& event) override;
-  base::string16 GetTitle() override;
   ash::ShelfMenuModel* CreateApplicationMenu(int event_flags) override;
-  bool IsDraggable() override;
-  bool ShouldShowTooltip() override;
 
  protected:
   // AppWindowLauncherItemController:
   void OnWindowRemoved(ui::BaseWindow* window) override;
 
  private:
   using WindowToAppWindow =
       std::map<const ui::BaseWindow*, extensions::AppWindow*>;
 
   WindowToAppWindow window_to_app_window_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionAppWindowLauncherItemController);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_EXTENSION_APP_WINDOW_LAUNCHER_ITEM_CONTROLLER_H_