Implements hook_user_view().
function user_user_view(UserInterface $account, EntityDisplay $display) {
if ($display
->getComponent('member_for')) {
$account->content['member_for'] = array(
'#type' => 'item',
'#title' => t('Member for'),
'#markup' => format_interval(REQUEST_TIME - $account->created),
);
}
}