7 files declare their use of ArgumentPluginBase

ArgumentDefaultPluginBase.php in drupal/core/modules/views/lib/Drupal/views/Plugin/views/argument_default/ArgumentDefaultPluginBase.php
Definition of Drupal\views\Plugin\views\argument_default\ArgumentDefaultPluginBase.
ArgumentValidatorPluginBase.php in drupal/core/modules/views/lib/Drupal/views/Plugin/views/argument_validator/ArgumentValidatorPluginBase.php
Definition of Drupal\views\Plugin\views\argument_validator\ArgumentValidatorPluginBase.
IndexTidDepth.php in drupal/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/views/argument/IndexTidDepth.php
Definition of Drupal\taxonomy\Plugin\views\argument\IndexTidDepth.
IndexTidDepthModifier.php in drupal/core/modules/taxonomy/lib/Drupal/taxonomy/Plugin/views/argument/IndexTidDepthModifier.php
Definition of Drupal\taxonomy\Plugin\views\argument\IndexTidDepthModifier.
LanguageArgument.php in drupal/core/modules/language/lib/Drupal/language/Plugin/views/argument/LanguageArgument.php
Contains Drupal\language\Plugin\views\argument\LanguageArgument.
Search.php in drupal/core/modules/search/lib/Drupal/search/Plugin/views/argument/Search.php
Definition of Drupal\search\Plugin\views\argument\Search.
UserUid.php in drupal/core/modules/comment/lib/Drupal/comment/Plugin/views/argument/UserUid.php
Definition of Drupal\comment\Plugin\views\argument\UserUid.