ash: Remove ShelfModel id conversion functions.

chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.cc

Index: chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.cc
diff --git a/chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.cc b/chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.cc
index cc480b7427e3ec2cb2a9078371bec849e161934a..b395f4700a0dd585d59e642c1a846d535a1fdf62 100644
--- a/chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.cc
+++ b/chrome/browser/ui/ash/launcher/arc_app_window_launcher_controller.cc
@@ -654,13 +654,12 @@ ArcAppWindowLauncherController::AttachControllerToTask(
       base::MakeUnique<ArcAppWindowLauncherItemController>(
           app_shelf_id.ToString());
   ArcAppWindowLauncherItemController* item_controller = controller.get();
-  ash::ShelfModel* shelf_model = ash::Shell::Get()->shelf_model();
-  const ash::ShelfID shelf_id =
-      shelf_model->GetShelfIDForAppID(app_shelf_id.ToString());
-  if (shelf_id.IsNull()) {
+  const ash::ShelfID shelf_id(app_shelf_id.ToString());
+  if (owner()->GetItem(shelf_id) == nullptr) {

[James Cook, 2017/05/10 02:51:18]

Yeah, I think HasItem() would be easier to read.

"== nullptr" makes me think of Java code.

[msw, 2017/05/10 18:21:53]

I'm using TRUE/FALSE for test expectations, and I simplified this.

[James Cook, 2017/05/10 19:29:35]

Yeah, I think the TRUE/FALSE works well enough.

     owner()->CreateAppLauncherItem(std::move(controller), ash::STATUS_RUNNING);
   } else {
-    shelf_model->SetShelfItemDelegate(shelf_id, std::move(controller));
+    owner()->shelf_model()->SetShelfItemDelegate(shelf_id,
+                                                 std::move(controller));
     owner()->SetItemStatus(shelf_id, ash::STATUS_RUNNING);
   }
   item_controller->AddTaskId(task_id);
@@ -673,12 +672,9 @@ void ArcAppWindowLauncherController::RegisterApp(
   AppWindow* app_window = app_window_info->app_window();
   ArcAppWindowLauncherItemController* controller =
       AttachControllerToTask(app_window->task_id(), *app_window_info);
-  DCHECK(controller);
-
-  const ash::ShelfID shelf_id =
-      ash::Shell::Get()->shelf_model()->GetShelfIDForAppID(
-          controller->app_id());
-  DCHECK(!shelf_id.IsNull());
+  DCHECK(!controller->app_id().empty());
+  const ash::ShelfID shelf_id(controller->app_id());
+  DCHECK_NE(nullptr, owner()->GetItem(shelf_id));
 
   controller->AddWindow(app_window);
   owner()->SetItemStatus(shelf_id, ash::STATUS_RUNNING);