MDL-25394 Tidied up several things in order to get this integrated

theme/switchdevice.php

@@ -0,0 +1,33 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * This code processes switch device requests-> ... -> Theme selector UI.
+ * 
+ * This script doesn't require login as not logged in users should still
+ * be able to switch the device theme they are using.
+ */
+
+require('../config.php');
+
+$url       = required_param('url', PARAM_LOCALURL);
+$newdevice = required_param('device', PARAM_TEXT);
+
+require_sesskey();
+
+set_user_device_type($newdevice);
+
+redirect($url);