ash: Remove ShelfModel id conversion functions.

chrome/browser/ui/ash/app_list/app_list_controller_ash.cc

Index: chrome/browser/ui/ash/app_list/app_list_controller_ash.cc
diff --git a/chrome/browser/ui/ash/app_list/app_list_controller_ash.cc b/chrome/browser/ui/ash/app_list/app_list_controller_ash.cc
index d02eeaadddb88eaa79e9ab3dfcfabcd3663fed5b..c944f12f1860fc7b0d712516420ae6a68549daf3 100644
--- a/chrome/browser/ui/ash/app_list/app_list_controller_ash.cc
+++ b/chrome/browser/ui/ash/app_list/app_list_controller_ash.cc
@@ -42,9 +42,7 @@ bool AppListControllerDelegateAsh::IsAppPinned(const std::string& app_id) {
 }
 
 bool AppListControllerDelegateAsh::IsAppOpen(const std::string& app_id) const {
-  ash::ShelfID id =
-      ash::Shell::Get()->shelf_model()->GetShelfIDForAppID(app_id);
-  return !id.IsNull() && ChromeLauncherController::instance()->IsOpen(id);
+  return ChromeLauncherController::instance()->IsOpen(ash::ShelfID(app_id));
 }
 
 void AppListControllerDelegateAsh::PinApp(const std::string& app_id) {