Form constructor.
array $form: An associative array containing the structure of the form.
array $form_state: An associative array containing the current state of the form.
array The form structure.
Overrides FormInterface::buildForm
public function buildForm(array $form, array &$form_state, FieldInstanceInterface $field_instance = NULL) {
$this->instance = $form_state['instance'] = $field_instance;
form_load_include($form_state, 'inc', 'field_ui', 'field_ui.admin');
}