Use Ash's ShelfWindowWatcher for app panel windows.

chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl.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 "chrome/browser/ui/ash/launcher/chrome_launcher_controller_impl.h"
 
 #include <stddef.h>
 
 #include <vector>
 
@@ skipping 431 matching lines @@
 }
 
 void ChromeLauncherControllerImpl::Launch(ash::ShelfID id, int event_flags) {
   LauncherItemController* controller = GetLauncherItemController(id);
   if (!controller)
     return;  // In case invoked from menu and item closed while menu up.
   controller->Launch(ash::LAUNCH_FROM_UNKNOWN, event_flags);
 }
 
 void ChromeLauncherControllerImpl::Close(ash::ShelfID id) {
-  LauncherItemController* controller = GetLauncherItemController(id);
-  if (!controller)
+  ash::ShelfItemDelegate* delegate = model_->GetShelfItemDelegate(id);
+  if (!delegate)
     return;  // May happen if menu closed.
-  controller->Close();
+  delegate->Close();
 }
 
 bool ChromeLauncherControllerImpl::IsOpen(ash::ShelfID id) {
-  LauncherItemController* controller = GetLauncherItemController(id);
-  if (!controller)
-    return false;
-  return controller->IsOpen();
+  ash::ShelfItemDelegate* delegate = model_->GetShelfItemDelegate(id);
+  return delegate && delegate->IsOpen();
 }
 
 bool ChromeLauncherControllerImpl::IsPlatformApp(ash::ShelfID id) {
   if (!HasShelfIDToAppIDMapping(id))
     return false;
 
   std::string app_id = GetAppIDForShelfID(id);
   const Extension* extension = GetExtensionForAppID(app_id, profile());
   // An extension can be synced / updated at any time and therefore not be
   // available.
@@ skipping 1092 matching lines @@
     if (index == -1)
       continue;
     ash::ShelfItem item = model_->items()[index];
     item.image = image;
     if (arc_deferred_launcher_)
       arc_deferred_launcher_->MaybeApplySpinningEffect(id, &item.image);
     model_->Set(index, item);
     // It's possible we're waiting on more than one item, so don't break.
   }
 }