only in patch2:
unchanged:
--- a/core/modules/content_translation/src/Tests/ContentTestTranslationUITest.php
+++ b/core/modules/content_translation/src/Tests/ContentTestTranslationUITest.php
@@ -26,7 +26,7 @@ class ContentTestTranslationUITest extends ContentTranslationUITest {
    */
   protected function setUp() {
     // Use the entity_test_mul as this has multilingual property support.
-    $this->entityTypeId = 'entity_test_mul';
+    $this->entityTypeId = 'entity_test_mul_changed';
     parent::setUp();
   }
 
only in patch2:
unchanged:
--- a/core/modules/shortcut/src/Tests/ShortcutTranslationUITest.php
+++ b/core/modules/shortcut/src/Tests/ShortcutTranslationUITest.php
@@ -8,6 +8,7 @@
 namespace Drupal\shortcut\Tests;
 
 use Drupal\content_translation\Tests\ContentTranslationUITest;
+use Drupal\Core\Entity\EntityChangedInterface;
 use Drupal\Core\Language\Language;
 
 /**
@@ -102,4 +103,16 @@ protected function doTestTranslationEdit() {
     }
   }
 
+  /**
+   * Tests the basic translation workflow.
+   */
+  protected function doTestTranslationChanged() {
+    $entity = entity_load($this->entityTypeId, $this->entityId, TRUE);
+
+    $this->assertFalse(
+      $entity instanceof EntityChangedInterface,
+      format_string('%entity is not implementing EntityChangedInterface.' , array('%entity' => $this->entityTypeId))
+    );
+  }
+
 }
only in patch2:
unchanged:
--- a/core/modules/system/tests/modules/entity_test/entity_test.module
+++ b/core/modules/system/tests/modules/entity_test/entity_test.module
@@ -58,6 +58,7 @@ function entity_test_entity_types($filter = NULL) {
   if ($filter != ENTITY_TEST_TYPES_REVISABLE) {
     $types[] = 'entity_test_mul';
     $types[] = 'entity_test_mul_langcode_key';
+    $types[] = 'entity_test_mul_changed';
   }
   if ($filter != ENTITY_TEST_TYPES_MULTILINGUAL) {
     $types[] = 'entity_test_rev';
only in patch2:
unchanged:
--- /dev/null
+++ b/core/modules/system/tests/modules/entity_test/src/Entity/EntityTestMulChanged.php
@@ -0,0 +1,74 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\entity_test\Entity\EntityTestMulDefaultValue.
+ */
+
+namespace Drupal\entity_test\Entity;
+
+use Drupal\Core\Entity\EntityChangedInterface;
+use Drupal\Core\Entity\EntityChangedTrait;
+use Drupal\Core\Entity\EntityTypeInterface;
+use Drupal\Core\Field\BaseFieldDefinition;
+
+/**
+ * Defines the test entity class.
+ *
+ * @ContentEntityType(
+ *   id = "entity_test_mul_changed",
+ *   label = @Translation("Test entity - data table"),
+ *   handlers = {
+ *     "view_builder" = "Drupal\entity_test\EntityTestViewBuilder",
+ *     "access" = "Drupal\entity_test\EntityTestAccessControlHandler",
+ *     "form" = {
+ *       "default" = "Drupal\entity_test\EntityTestForm",
+ *       "delete" = "Drupal\entity_test\EntityTestDeleteForm"
+ *     },
+ *     "translation" = "Drupal\content_translation\ContentTranslationHandler",
+ *     "views_data" = "Drupal\views\EntityViewsData"
+ *   },
+ *   base_table = "entity_test_mul_changed",
+ *   data_table = "entity_test_mul_changed_property",
+ *   translatable = TRUE,
+ *   entity_keys = {
+ *     "id" = "id",
+ *     "uuid" = "uuid",
+ *     "bundle" = "type",
+ *     "label" = "name",
+ *     "langcode" = "langcode"
+ *   },
+ *   links = {
+ *     "canonical" = "/entity_test_mul_changed/manage/{entity_test_mul_changed}",
+ *     "edit-form" = "/entity_test_mul_changed/manage/{entity_test_mul_changed}",
+ *     "delete-form" = "/entity_test/delete/entity_test_mul_changed/{entity_test_mul_changed}",
+ *   },
+ *   field_ui_base_route = "entity.entity_test_mul_changed.admin_form",
+ * )
+ */
+class EntityTestMulChanged extends EntityTestMul implements EntityChangedInterface {
+
+  use EntityChangedTrait;
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function baseFieldDefinitions(EntityTypeInterface $entity_type) {
+    $fields = parent::baseFieldDefinitions($entity_type);
+
+    $fields['changed'] = BaseFieldDefinition::create('changed')
+      ->setLabel(t('Changed'))
+      ->setDescription(t('The time that the entity was last edited.'))
+      ->setTranslatable(TRUE);
+
+    return $fields;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getChangedTime() {
+    return $this->get('changed')->value;
+  }
+
+}