Implements hook_page_build().
Adds the drupal.contextual-links library to the page for any user who has the 'access contextual links' permission.
function contextual_page_build(&$page) {
if (!user_access('access contextual links')) {
return;
}
$page['#attached']['library'][] = array(
'contextual',
'drupal.contextual-links',
);
}