Implements hook_preprocess().
contextual_pre_render_placeholder()
\Drupal\contextual\ContextualController::render()
function contextual_preprocess(&$variables, $hook, $info) {
// Determine the primary theme function argument.
if (!empty($info['variables'])) {
$keys = array_keys($info['variables']);
$key = $keys[0];
}
elseif (!empty($info['render element'])) {
$key = $info['render element'];
}
if (!empty($key) && isset($variables[$key])) {
$element = $variables[$key];
}
if (isset($element) && is_array($element) && !empty($element['#contextual_links'])) {
// Mark this element as potentially having contextual links attached to it.
$variables['attributes']['class'][] = 'contextual-region';
// Renders a contextual links placeholder unconditionally, thus not breaking
// the render cache. Although the empty placeholder is rendered for all
// users, contextual_page_build() only adds the drupal.contextual-links
// library for users with the 'access contextual links' permission, thus
// preventing unnecessary HTTP requests for users without that permission.
$variables['title_suffix']['contextual_links'] = array(
'#type' => 'contextual_links_placeholder',
'#id' => _contextual_links_to_id($element['#contextual_links']),
);
}
}