chromium/chrome/browser/ash/dbus/org.chromium.KioskAppService.conf

<!DOCTYPE busconfig PUBLIC "-//freedesktop//DTD D-BUS Bus Configuration 1.0//EN"
  "http://www.freedesktop.org/standards/dbus/1.0/busconfig.dtd">
<!--
  Copyright 2017 The Chromium Authors
  Use of this source code is governed by a BSD-style license that can be
  found in the LICENSE file.

  This file will be installed at /opt/google/chrome/dbus on Chrome OS.
-->
<busconfig>
  <policy user="chronos">
    <allow own="org.chromium.KioskAppService"/>
  </policy>

  <!--
    update_engine uses this service to query required platform version for
    the auto launched kiosk app.
  -->
  <policy user="root">
    <allow send_destination="org.chromium.KioskAppService"
           send_interface="org.chromium.KioskAppServiceInterface"/>
  </policy>
</busconfig>