Issue #2002338 by schiavone, elvis2: Rename Views method add_tag() to addTag().

core/modules/views/lib/Drupal/views/Plugin/views/query/Sql.php

@@ -1055,7 +1055,7 @@ function get_field_alias($table_alias, $field) {
    *
    * @see SelectQuery::addTag()
    */
-  function add_tag($tag) {
+  public function addTag($tag) {
     $this->tags[] = $tag;
   }
 

core/modules/views/lib/Drupal/views/Plugin/views/relationship/RelationshipPluginBase.php

@@ -140,7 +140,7 @@ public function query() {
     // Add access tags if the base table provide it.
     if (empty($this->query->options['disable_sql_rewrite']) && isset($table_data['table']['base']['access query tag'])) {
       $access_tag = $table_data['table']['base']['access query tag'];
-      $this->query->add_tag($access_tag);
+      $this->query->addTag($access_tag);
     }
   }