Issue #2744307 by socketwench: Removed hook_flag_validate().

}

/**

 * Perform custom validation on a flag before flagging/unflagging.

 *

 * @param string $action

 *   The action about to be carried out. Either 'flag' or 'unflag'.

 * @param \Drupal\flag\FlagInterface $flag

 *   The flag object.

 * @param int $entity_id

 *   The id of the entity the user is trying to flag or unflag.

 * @param \Drupal\Core\Session\AccountInterface $account

 *   The user account performing the action.

 * @param bool $skip_permission_check

 *   TRUE to skip the permission check, FALSE otherwise.

 * @param \Drupal\flag\FlaggingInterface $flagging

 *   The flagging entity.

 *

 * @return array|null

 *   (optional) array: textual error with the error-name as the key.

 *   If the error name is 'access-denied' and javascript is disabled,

 *   drupal_access_denied will be called and a 403 will be returned.

 *   If validation is successful, do not return a value.

 */

function hook_flag_validate($action, FlagInterface $flag, $entity_id,

                            AccountInterface $account, $skip_permission_check,

                            FlaggingInterface $flagging) {

}

/**

 * Alter other modules' definitions of flag link types.

 *