Issue #2061935 by m1r1k, danylevskyi, joelpittet: Remove calls to deprecated...

Issue #2061935 by m1r1k, danylevskyi, joelpittet: Remove calls to deprecated global $user in forum module.

core/modules/forum/forum.module

@@ -149,7 +149,7 @@ function forum_menu() {
  * Implements hook_menu_local_tasks().
  */
 function forum_menu_local_tasks(&$data, $route_name) {
-  global $user;
+  $user = \Drupal::currentUser();
 
   // Add action link to 'node/add/forum' on 'forum' sub-pages.
   if (in_array($route_name, array('forum.index', 'forum.page'))) {
@@ -682,7 +682,7 @@ function template_preprocess_forums(&$variables) {
  *   - tid: Taxonomy term ID of the current forum.
  */
 function template_preprocess_forum_list(&$variables) {
-  global $user;
+  $user = \Drupal::currentUser();
   $row = 0;
   // Sanitize each forum so that the template can safely print the data.
   foreach ($variables['forums'] as $id => $forum) {

core/modules/forum/lib/Drupal/forum/ForumManager.php

@@ -139,7 +139,8 @@ public function getTopics($tid) {
     $forum_per_page = $config->get('topics.page_limit');
     $sortby = $config->get('topics.order');
 
-    global $user, $forum_topic_list_header;
+    global $forum_topic_list_header;
+    $user = \Drupal::currentUser();
 
     $forum_topic_list_header = array(
       array('data' => $this->t('Topic'), 'field' => 'f.title'),
@@ -326,7 +327,7 @@ protected function numberNew($nid, $timestamp) {
    *   previously viewed the node; otherwise HISTORY_READ_LIMIT.
    */
   protected function lastVisit($nid) {
-    global $user;
+    $user = \Drupal::currentUser();
 
     if (empty($this->history[$nid])) {
       $result = $this->connection->select('history', 'h')