Issue #1810330 by c4doug, plach, YesCT: Remove EntityTranslationControllerInterface::removeTranslation().

core/modules/content_translation/content_translation.pages.inc

@@ -265,7 +265,7 @@ function content_translation_delete_confirm_submit(array $form, array &$form_sta
   $controller = content_translation_controller($entity->entityType());
 
   // Remove the translated values.
-  $controller->removeTranslation($entity, $language->id);
+  $entity->removeTranslation($language->id);
   $entity->save();
 
   // Remove any existing path alias for the removed translation.

core/modules/content_translation/lib/Drupal/content_translation/ContentTranslationController.php

@@ -42,13 +42,6 @@ class ContentTranslationController implements ContentTranslationControllerInterf
     $this->entityInfo = $entity_info;
   }
 
-  /**
-   * {@inheritdoc}
-   */
-  public function removeTranslation(EntityInterface $entity, $langcode) {
-    $entity->removeTranslation($langcode);
-  }
-
   /**
    * Implements ContentTranslationControllerInterface::retranslate().
    */

core/modules/content_translation/lib/Drupal/content_translation/ContentTranslationControllerInterface.php

@@ -139,16 +139,6 @@ interface ContentTranslationControllerInterface {
    */
   public function getSourceLangcode(array $form_state);
 
-  /**
-   * Removes the translation values from the given entity.
-   *
-   * @param \Drupal\Core\Entity\EntityInterface $entity
-   *   The entity whose values should be removed.
-   * @param string $langcode
-   *   The language code identifying the translation being deleted.
-   */
-  public function removeTranslation(EntityInterface $entity, $langcode);
-
   /**
    * Marks translations as outdated.
    *