ConfirmFormBase::buildForm

public ConfirmFormBase::buildForm(array $form, FormStateInterface $form_state)

public function buildForm(array $form, FormStateInterface $form_state) {
  $form['#title'] = $this->getQuestion();

  $form['#attributes']['class'][] = 'confirmation';
  $form['description'] = array('#markup' => $this->getDescription());
  $form[$this->getFormName()] = array('#type' => 'hidden', '#value' => 1);

  $form['actions'] = array('#type' => 'actions');
  $form['actions']['submit'] = array(
    '#type' => 'submit',
    '#value' => $this->getConfirmText(),
    '#button_type' => 'primary',
  );

  $form['actions']['cancel'] = ConfirmFormHelper::buildCancelLink($this, $this->getRequest());

  // By default, render the form using theme_confirm_form().
  if (!isset($form['#theme'])) {
    $form['#theme'] = 'confirm_form';
  }
  return $form;
}