- Updates Daemon to execute workers via WP's action hook

- Bootstraps Scheduler class

lib/Cron/Workers/Scheduler.php

@@ -0,0 +1,27 @@
+<?php
+namespace MailPoet\Cron\Workers;
+
+use MailPoet\Cron\CronHelper;
+use MailPoet\Models\Setting;
+use MailPoet\Util\Security;
+
+if(!defined('ABSPATH')) exit;
+
+class Scheduler {
+  public $timer;
+
+  function __construct($timer = false) {
+    $this->timer = ($timer) ? $timer : microtime(true);
+    CronHelper::checkExecutionTimer($this->timer);
+  }
+
+  function process() {
+  }
+
+  function checkExecutionTimer() {
+    $elapsed_time = microtime(true) - $this->timer;
+    if($elapsed_time >= CronHelper::daemon_execution_limit) {
+      throw new \Exception(__('Maximum execution time reached.'));
+    }
+  }
+}