Issue #3142095: Automated Drupal 9 compatibility fixes

views_dependent_filter.info.yml

@@ -7,5 +7,6 @@ description: 'views dependent filter'
 # Information added by Drupal.org packaging script on 2017-07-03
 version: '8.x-1.x-dev'
 core: '8.x'
+core_version_requirement: ^8 || ^9
 project: 'views_dependent_filter'
 datestamp: 1499099876

views_dependent_filter.module

@@ -12,7 +12,7 @@ use Drupal\Component\Utility\Unicode;
 /**
  * After build form processor for the views exposed form.
  */
-function views_dependent_filters_exposed_form_after_build(&$form, \Drupal\Core\Form\FormStateInterface $form_state) {
+function views_dependent_filters_exposed_form_after_build(&$form, FormStateInterface $form_state) {
   // We may have multiple dependency info arrays from more than one copies
   // of the views_dependent_filters_handler_filter_dependent handler.
   foreach ($form_state->dependent_exposed_filters as $dependency_info) {
@@ -46,7 +46,7 @@ function views_dependent_filters_exposed_form_after_build(&$form, \Drupal\Core\F
  * it from the original input.
  */
 function views_dependent_filters_recreate_html_id($id) {
-  $id = strtr(Unicode::strtolower($id), array(' ' => '-', '_' => '-', '[' => '-', ']' => ''));
+  $id = strtr(mb_strtolower($id), array(' ' => '-', '_' => '-', '[' => '-', ']' => ''));
 
   // As defined in http://www.w3.org/TR/html4/types.html#type-name, HTML IDs can
   // only contain letters, digits ([0-9]), hyphens ("-"), underscores ("_"),