Issue #3374730: Failing due to nonexistant getType()

Correct the syntax for checking the display plugin ID.

Closes #3374730

views_pdf.module

@@ -20,8 +20,8 @@ function views_pdf_help($route_name, RouteMatchInterface $route_match) {
       $output .= '<li>'.t('Complex tables make troubles.').'</li>';
       $output .= '<li>'.t('Vector graphics can not be implemented, therefore the printing of the document can be problematic.').'</li>';
       $output .= '<li>'.t('You are limited by HTML capabilities.').'</li>'.'</ul>';
-      $output .= '<p>'.t('You can also specify a background PDF document. This enables you to put unlimited static content to the dynamic PDF. 
-                          This static PDF can be exchanged dynamically by using a File Field. 
+      $output .= '<p>'.t('You can also specify a background PDF document. This enables you to put unlimited static content to the dynamic PDF.
+                          This static PDF can be exchanged dynamically by using a File Field.
                           The PDF can be created by any PDF creator such as Adobe Acrobat Professional or Open Office.').'</p>';
       return $output;
   }
@@ -55,7 +55,7 @@ function views_pdf_form_view_preview_form_alter(&$form, \Drupal\Core\Form\FormSt
   $viewUI = $form_state->getStorage()['view'];
   $view = $viewUI->getExecutable();
 
-  if ('pdf' === $view->display_handler->getType()) {
+  if ('pdf' === $view->getDisplay()->getPluginId()) {
     $form['controls']['live_preview']['#default_value'] = FALSE;
   }
 }