arc: Fix regression in handling ARC shelf item.

chrome/browser/ui/ash/launcher/arc_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_ARC_APP_WINDOW_LAUNCHER_ITEM_CONTROLLER_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_WINDOW_LAUNCHER_ITEM_CONTROLLER_H_
 
 #include <string>
 #include <unordered_set>
 
@@ skipping 10 matching lines @@
                                      ChromeLauncherController* controller);
 
   ~ArcAppWindowLauncherItemController() override;
 
   // LauncherItemController overrides:
   void ItemSelected(std::unique_ptr<ui::Event> event,
                     int64_t display_id,
                     ash::ShelfLaunchSource source,
                     const ItemSelectedCallback& callback) override;
   MenuItemList GetAppMenuItems(int event_flags) override;
+  void ExecuteCommand(uint32_t command_id, int32_t event_flags) override;
 
   void AddTaskId(int task_id);
   void RemoveTaskId(int task_id);
   bool HasAnyTasks() const;
 
  private:
   std::unordered_set<int> task_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcAppWindowLauncherItemController);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_WINDOW_LAUNCHER_ITEM_CONTROLLER_H_