mash: Remove ChromeLauncherController's |id_to_item_controller_map_|.

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

 // 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.
 
 #include "ash/common/shelf/shelf_delegate.h"
 #include "ash/public/cpp/shelf_item_delegate.h"
 #include "ash/shell.h"
 #include "ash/wm/window_util.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
@@ skipping 241 matching lines @@
     app_instance_observer()->OnInstanceReady();
   }
 
   void StopInstance() {
     arc_session_manager()->Shutdown();
     app_instance_observer()->OnInstanceClosed();
   }
 
   ash::ShelfItemDelegate* GetAppItemController(const std::string& id) {
     const ash::ShelfID shelf_id = shelf_delegate()->GetShelfIDForAppID(id);
-    if (!shelf_id)
-      return nullptr;
-    return chrome_controller()->GetShelfItemDelegate(shelf_id);
+    return ash::Shell::Get()->shelf_model()->GetShelfItemDelegate(shelf_id);
   }
 
   ArcAppListPrefs* app_prefs() { return ArcAppListPrefs::Get(profile()); }
 
   // Returns as AppHost interface in order to access to private implementation
   // of the interface.
   arc::mojom::AppHost* app_host() { return app_prefs(); }
 
   // Returns as AppInstance observer interface in order to access to private
   // implementation of the interface.
@@ skipping 271 matching lines @@
   app_host()->OnTaskDestroyed(2);
   EXPECT_EQ(controller2, GetAppItemController(shelf_id2));
   // Destroy task #2, this kills shelf group 2
   app_host()->OnTaskDestroyed(3);
   EXPECT_FALSE(GetAppItemController(shelf_id2));
 
   // Disable ARC, this removes app and as result kills shelf group 3.
   arc::SetArcPlayStoreEnabledForProfile(profile(), false);
   EXPECT_FALSE(GetAppItemController(shelf_id3));
 }