8 files declare their use of ProcessDecorator

DefaultsTestPluginManager.php in drupal/core/modules/system/tests/modules/plugin_test/lib/Drupal/plugin_test/Plugin/DefaultsTestPluginManager.php
Contains Drupal\plugin_test\Plugin\DefaultsTestPluginManager.
EntityManager.php in drupal/core/lib/Drupal/Core/Entity/EntityManager.php
Contains \Drupal\Core\Entity\EntityManager.
FormatterPluginManager.php in drupal/core/modules/field/lib/Drupal/field/Plugin/Type/Formatter/FormatterPluginManager.php
Definition of Drupal\field\Plugin\Type\Formatter\FormatterPluginManager..
JoinManager.php in drupal/core/modules/views/lib/Drupal/views/Plugin/Type/JoinManager.php
Definition of Drupal\views\Plugin\Type\JoinManager.
LayoutManager.php in drupal/core/modules/layout/lib/Drupal/layout/Plugin/Type/LayoutManager.php
Definition of Drupal\layout\Plugin\Type\LayoutManager.
PluginManager.php in drupal/core/modules/views/lib/Drupal/views/Plugin/Type/PluginManager.php
Definition of Drupal\views\Plugin\Type\PluginManager.
WidgetPluginManager.php in drupal/core/modules/field/lib/Drupal/field/Plugin/Type/Widget/WidgetPluginManager.php
Definition of Drupal\field\Plugin\Type\Widget\WidgetPluginManager.
WizardManager.php in drupal/core/modules/views/lib/Drupal/views/Plugin/Type/WizardManager.php
Definition of Drupal\views\Plugin\Type\WizardManager.