mash: Remove shelf app menu item objects.

ash/shell/window_watcher_shelf_item_delegate.cc

 // Copyright 2013 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.
 
 #include "ash/shell/window_watcher_shelf_item_delegate.h"
 
 #include "ash/shell/window_watcher.h"
 #include "ash/wm/window_util.h"
 #include "ui/aura/window.h"
 
@@ skipping 22 matching lines @@
   wm::ActivateWindow(window);
   return SHELF_ACTION_WINDOW_ACTIVATED;
 }
 
 ShelfAppMenuItemList WindowWatcherShelfItemDelegate::GetAppMenuItems(
     int event_flags) {
   // Return an empty item list to avoid showing an application menu.
   return ShelfAppMenuItemList();
 }
 
+void WindowWatcherShelfItemDelegate::ExecuteCommand(uint32_t command_id,
+                                                    int event_flags) {
+  // This delegate does not support showing an application menu.
+  NOTIMPLEMENTED();
+}
+
 void WindowWatcherShelfItemDelegate::Close() {}
 
 }  // namespace shell
 }  // namespace ash