class CKEditorPluginBase

abstract class CKEditorPluginBase extends PluginBase implements CKEditorPluginInterface, CKEditorPluginButtonsInterface {
    
    /**
     * The module list service.
     *
     * @var \Drupal\Core\Extension\ModuleExtensionList
     */
    protected $moduleList;
    
    /**
     * Gets the module list service.
     *
     * @return \Drupal\Core\Extension\ModuleExtensionList
     *   The module extension list service.
     */
    protected function getModuleList() : ModuleExtensionList {
        if (!$this->moduleList) {
            $this->moduleList = \Drupal::service('extension.list.module');
        }
        return $this->moduleList;
    }
    
    /**
     * Gets the Drupal-root relative installation directory of a module.
     *
     * @param string $module_name
     *   The machine name of the module.
     *
     * @return string
     *   The module installation directory.
     *
     * @throws \InvalidArgumentException
     *   If there is no extension with the supplied machine name.
     *
     * @see \Drupal\Core\Extension\ExtensionList::getPath()
     */
    protected function getModulePath(string $module_name) : string {
        return $this->getModuleList()
            ->getPath($module_name);
    }
    
    /**
     * {@inheritdoc}
     */
    public function isInternal() {
        return FALSE;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getDependencies(Editor $editor) {
        return [];
    }
    
    /**
     * {@inheritdoc}
     */
    public function getLibraries(Editor $editor) {
        return [];
    }

}