MDL-81960 core: Move progress_trace classes to legacy autoloader

lib/classes/output/progress_trace.php

@@ -0,0 +1,41 @@
+<?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/>.
+
+/**
+ * Progress trace class.
+ *
+ * Use this class from long operations where you want to output occasional information about
+ * what is going on, but don't know if, or in what format, the output should be.
+ *
+ * @copyright 2009 Tim Hunt
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @package core
+ */
+abstract class progress_trace {
+    /**
+     * Output an progress message in whatever format.
+     *
+     * @param string $message the message to output.
+     * @param integer $depth indent depth for this message.
+     */
+    abstract public function output($message, $depth = 0);
+
+    /**
+     * Called when the processing is finished.
+     */
+    public function finished() {
+    }
+}