Use OnceCallback on Mojo interfaces in //ash

chrome/browser/ui/ash/launcher/arc_playstore_shortcut_launcher_item_controller.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 "chrome/browser/ui/ash/launcher/arc_playstore_shortcut_launcher_item_controller.h"
 
+#include <utility>
+
 #include "base/memory/ptr_util.h"
 #include "chrome/browser/chromeos/arc/arc_support_host.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/app_list/arc/arc_app_launcher.h"
 #include "chrome/browser/ui/app_list/arc/arc_app_utils.h"
 #include "chrome/browser/ui/ash/launcher/chrome_launcher_controller.h"
 #include "ui/events/event_constants.h"
 
 ArcPlaystoreShortcutLauncherItemController::
     ArcPlaystoreShortcutLauncherItemController()
     : AppShortcutLauncherItemController(
           ash::ShelfID(ArcSupportHost::kHostAppId)) {}
 
 ArcPlaystoreShortcutLauncherItemController::
     ~ArcPlaystoreShortcutLauncherItemController() {}
 
 void ArcPlaystoreShortcutLauncherItemController::ItemSelected(
     std::unique_ptr<ui::Event> event,
     int64_t display_id,
     ash::ShelfLaunchSource source,
-    const ItemSelectedCallback& callback) {
+    ItemSelectedCallback callback) {
   if (!playstore_launcher_) {
     // Play Store launch request has never been scheduled.
     std::unique_ptr<ArcAppLauncher> playstore_launcher =
         base::MakeUnique<ArcAppLauncher>(
             ChromeLauncherController::instance()->profile(),
             arc::kPlayStoreAppId, true /* landscape_layout */,
             true /* deferred_launch_allowed */);
     // ArcAppLauncher may launch Play Store in case it exists already. In this
     // case this instance of ArcPlaystoreShortcutLauncherItemController may be
     // deleted. If Play Store does not exist at this moment, then let
     // |playstore_launcher_| wait until it appears.
     if (!playstore_launcher->app_launched())
       playstore_launcher_ = std::move(playstore_launcher);
   }
-  callback.Run(ash::SHELF_ACTION_NONE, base::nullopt);
+  std::move(callback).Run(ash::SHELF_ACTION_NONE, base::nullopt);
 }