diff --git a/core/config/schema/core.data_types.schema.yml b/core/config/schema/core.data_types.schema.yml
index 33369bd..4356141 100644
--- a/core/config/schema/core.data_types.schema.yml
+++ b/core/config/schema/core.data_types.schema.yml
@@ -374,6 +374,11 @@ field_config_base:
       label: 'Default value function'
     settings:
       type: field.[%parent.field_type].instance_settings
+    third_party_settings:
+      type: sequence
+      label: 'Third party settings'
+      sequence:
+        - type: field_config.third_party.[%key]
     field_type:
       type: string
       label: 'Field type'
diff --git a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
index 210e259..9916615 100644
--- a/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
+++ b/core/lib/Drupal/Core/Config/Entity/ConfigEntityBase.php
@@ -326,6 +326,13 @@ public function calculateDependencies() {
         }
       }
     }
+    if ($this instanceof ThirdPartySettingsInterface) {
+      // Configuration entities need to depend on the providers of any third
+      // parties that they store the configuration for.
+      foreach ($this->getThirdPartyProviders() as $provider) {
+        $this->addDependency('module', $provider);
+      }
+    }
     return $this->dependencies;
   }
 
diff --git a/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsException.php b/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsException.php
new file mode 100644
index 0000000..7320d81
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsException.php
@@ -0,0 +1,15 @@
+<?php
+
+/**
+ * @file
+ * Definition of Drupal\Core\Config\Entity\ThirdPartySettingsException.
+ */
+
+namespace Drupal\Core\Config\Entity;
+
+use Drupal\Core\Config\ConfigException;
+
+/**
+ * Exception thrown in relation to third party settings errors.
+ */
+class ThirdPartySettingsException extends ConfigException {}
diff --git a/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsInterface.php b/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsInterface.php
new file mode 100644
index 0000000..30109e0
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsInterface.php
@@ -0,0 +1,82 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Config\Entity\ThirdPartySettingsInterface.
+ */
+
+namespace Drupal\Core\Config\Entity;
+
+/**
+ * Interface for configuration entities to store third party information.
+ *
+ * A third party is a module that needs to store tightly coupled information to
+ * the configuration entity. For example, a module alters the node type form
+ * can use this to store its configuration so that it will be deployed with the
+ * node type.
+ */
+interface ThirdPartySettingsInterface {
+
+  /**
+   * Sets the value of a third-party setting.
+   *
+   * @param string $module
+   *   The module providing the third-party setting.
+   * @param string $key
+   *   The setting name.
+   * @param mixed $value
+   *   The setting value.
+   *
+   * @return $this
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  public function setThirdPartySetting($module, $key, $value);
+
+  /**
+   * Gets the value of a third-party setting.
+   *
+   * @param string $module
+   *   The module providing the third-party setting.
+   * @param string $key
+   *   The setting name.
+   * @param mixed $default
+   *   The default value
+   *
+   * @return mixed
+   *   The value.
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  public function getThirdPartySetting($module, $key, $default);
+
+  /**
+   * Unsets a third-party setting.
+   *
+   * @param string $module
+   *   The module providing the third-party setting.
+   * @param string $key
+   *   The setting name.
+   *
+   * @return mixed
+   *   The value.
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  public function unsetThirdPartySetting($module, $key);
+
+  /**
+   * Gets the list of third parties that store information.
+   *
+   * @return array
+   *   The list of third parties.
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  public function getThirdPartyProviders();
+
+}
diff --git a/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsTrait.php b/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsTrait.php
new file mode 100644
index 0000000..6433e64
--- /dev/null
+++ b/core/lib/Drupal/Core/Config/Entity/ThirdPartySettingsTrait.php
@@ -0,0 +1,128 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Config\Entity\ThirdPartySettingsTrait.
+ */
+
+namespace Drupal\Core\Config\Entity;
+
+/**
+ * Provides generic implementation of ThirdPartySettingsInterface.
+ *
+ * The default property used to store third party settings is
+ * 'third_party_settings'. This property should be an array. To override for a
+ * specific implement set $thirdPartySettingKey in the constructor.
+ *
+ * @see \Drupal\Core\Config\Entity\ThirdPartySettingsInterface
+ */
+trait ThirdPartySettingsTrait {
+
+  /**
+   * Name of the property on the class that stores third party settings.
+   *
+   * The property named should be an array.
+   *
+   * @var string
+   */
+  protected $thirdPartySettingKey = 'third_party_settings';
+
+  /**
+   * Sets the value of a third-party setting.
+   *
+   * @param string $module
+   *   The module providing the third-party setting.
+   * @param string $key
+   *   The setting name.
+   * @param mixed $value
+   *   The setting value.
+   *
+   * @return $this
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  public function setThirdPartySetting($module, $key, $value) {
+    $this->checkThirdPartyArray();
+    $this->{$this->thirdPartySettingKey}[$module][$key] = $value;
+    return $this;
+  }
+
+  /**
+   * Gets the value of a third-party setting.
+   *
+   * @param string $module
+   *   The module providing the third-party setting.
+   * @param string $key
+   *   The setting name.
+   * @param mixed $default
+   *   The default value
+   *
+   * @return mixed
+   *   The value.
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  public function getThirdPartySetting($module, $key, $default = NULL) {
+    $this->checkThirdPartyArray();
+    if (isset($this->{$this->thirdPartySettingKey}[$module][$key])) {
+      return $this->{$this->thirdPartySettingKey}[$module][$key];
+    }
+    else {
+      return $default;
+    }
+  }
+
+  /**
+   * Unsets a third-party setting.
+   *
+   * @param string $module
+   *   The module providing the third-party setting.
+   * @param string $key
+   *   The setting name.
+   *
+   * @return mixed
+   *   The value.
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  public function unsetThirdPartySetting($module, $key) {
+    $this->checkThirdPartyArray();
+    unset($this->{$this->thirdPartySettingKey}[$module][$key]);
+    // If the third party is no longer storing any information completely remove
+    // the setting.
+    if (empty($this->{$this->thirdPartySettingKey}[$module])) {
+      unset($this->{$this->thirdPartySettingKey}[$module]);
+    }
+    return $this;
+  }
+
+  /**
+   * Gets the list of third parties that store information.
+   *
+   * @return array
+   *   The list of third parties.
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  public function getThirdPartyProviders() {
+    $this->checkThirdPartyArray();
+    return array_keys($this->{$this->thirdPartySettingKey});
+  }
+
+  /**
+   * Checks that the third party settings property is an array.
+   *
+   * @throws \Drupal\Core\Config\Entity\ThirdPartySettingsException
+   *   If the third party providers property is not an array.
+   */
+  protected function checkThirdPartyArray() {
+    if (!is_array($this->{$this->thirdPartySettingKey})) {
+      throw new ThirdPartySettingsException('Third party settings storage should be an array.');
+    }
+  }
+
+}
diff --git a/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php b/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
index 536a4cb..0836eaf 100644
--- a/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
+++ b/core/lib/Drupal/Core/Config/Schema/SchemaCheckTrait.php
@@ -80,11 +80,6 @@ protected function checkValue($key, $value) {
     $error_key = $this->configName . ':' . $key;
     $element = $this->schema->get($key);
     if ($element instanceof Undefined) {
-      // @todo Temporary workaround for https://www.drupal.org/node/2224761.
-      $key_parts = explode('.', $key);
-      if (array_pop($key_parts) == 'translation_sync' && strpos($this->configName, 'field.') === 0) {
-        return array();
-      }
       return array($error_key => 'Missing schema.');
     }
 
diff --git a/core/lib/Drupal/Core/Field/FieldConfigBase.php b/core/lib/Drupal/Core/Field/FieldConfigBase.php
index 1d12480..189b417 100644
--- a/core/lib/Drupal/Core/Field/FieldConfigBase.php
+++ b/core/lib/Drupal/Core/Field/FieldConfigBase.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Field;
 
 use Drupal\Core\Config\Entity\ConfigEntityBase;
+use Drupal\Core\Config\Entity\ThirdPartySettingsTrait;
 use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\EntityStorageInterface;
 use Drupal\Core\Field\TypedData\FieldItemDataDefinition;
@@ -16,6 +17,7 @@
  * Base class for configurable field definitions.
  */
 abstract class FieldConfigBase extends ConfigEntityBase implements FieldConfigInterface {
+  use ThirdPartySettingsTrait;
 
   /**
    * The instance ID.
@@ -97,6 +99,15 @@
   public $settings = array();
 
   /**
+   * Third party field-type specific settings.
+   *
+   * An arrays of key/value pairs keyed by provider.
+   *
+   * @var array
+   */
+  protected $third_party_settings = array();
+
+  /**
    * Flag indicating whether the field is required.
    *
    * TRUE if a value for this field is required when used with this bundle,
diff --git a/core/lib/Drupal/Core/Field/FieldConfigInterface.php b/core/lib/Drupal/Core/Field/FieldConfigInterface.php
index 1207356..93c71b5 100644
--- a/core/lib/Drupal/Core/Field/FieldConfigInterface.php
+++ b/core/lib/Drupal/Core/Field/FieldConfigInterface.php
@@ -8,6 +8,7 @@
 namespace Drupal\Core\Field;
 
 use Drupal\Core\Config\Entity\ConfigEntityInterface;
+use Drupal\Core\Config\Entity\ThirdPartySettingsInterface;
 
 /**
  * Defines an interface for configurable field definitions.
@@ -19,7 +20,7 @@
  * @see \Drupal\Core\Field\Entity\BaseFieldOverride
  * @see \Drupal\field\Entity\FieldInstanceConfig
  */
-interface FieldConfigInterface extends FieldDefinitionInterface, ConfigEntityInterface {
+interface FieldConfigInterface extends FieldDefinitionInterface, ConfigEntityInterface, ThirdPartySettingsInterface {
 
   /**
    * Sets the field definition label.
diff --git a/core/modules/content_translation/config/schema/content_translation.schema.yml b/core/modules/content_translation/config/schema/content_translation.schema.yml
new file mode 100644
index 0000000..6e4167e
--- /dev/null
+++ b/core/modules/content_translation/config/schema/content_translation.schema.yml
@@ -0,0 +1,12 @@
+# Schema for the Content Translation module.
+
+field_config.third_party.content_translation:
+  type: mapping
+  label: 'Content translation field settings'
+  mapping:
+    translation_sync:
+      type: sequence
+      label: 'Field properties for which to synchronize translations'
+      sequence:
+        - type: string
+          label: 'Field column for which to synchronize translations'
diff --git a/core/modules/content_translation/content_translation.admin.inc b/core/modules/content_translation/content_translation.admin.inc
index 36ac92e..86d355d 100644
--- a/core/modules/content_translation/content_translation.admin.inc
+++ b/core/modules/content_translation/content_translation.admin.inc
@@ -6,6 +6,7 @@
  */
 
 use Drupal\Component\Utility\String;
+use Drupal\Core\Config\Entity\ThirdPartySettingsInterface;
 use Drupal\Core\Entity\ContentEntityTypeInterface;
 use Drupal\Core\Field\FieldDefinitionInterface;
 use Drupal\Core\Form\FormStateInterface;
@@ -36,14 +37,16 @@ function content_translation_field_sync_widget(FieldDefinitionInterface $field)
       $default[$group] = !empty($info['translatable']) ? $group : FALSE;
     }
 
-    $settings = array('dependent_selectors' => array('instance[settings][translation_sync]' => array('file')));
+    $settings = array('dependent_selectors' => array('instance[third_party_settings][content_translation][translation_sync]' => array('file')));
 
-    $translation_sync = $field->getSetting('translation_sync');
+    if ($field instanceof ThirdPartySettingsInterface ) {
+      $default = $field->getThirdPartySetting('content_translation', 'translation_sync', $default);
+    }
     $element = array(
       '#type' => 'checkboxes',
       '#title' => t('Translatable elements'),
       '#options' => $options,
-      '#default_value' => !empty($translation_sync) ? $translation_sync : $default,
+      '#default_value' => $default,
       '#attached' => array(
         'library' => array(
           'content_translation/drupal.content_translation.admin',
@@ -313,9 +316,32 @@ function content_translation_form_language_content_settings_submit(array $form,
           }
         }
       }
+      if (isset($bundle_settings['translatable'])) {
+        // Store whether a bundle has translation enabled or not.
+        content_translation_set_config($entity_type_id, $bundle, 'enabled', $bundle_settings['translatable']);
+
+        // Save translation_sync settings.
+        if (!empty($bundle_settings['columns'])) {
+          foreach ($bundle_settings['columns'] as $field_name => $column_settings) {
+            $field_config = $fields[$field_name]->getConfig($bundle);
+            if ($field_config->isTranslatable()) {
+              $field_config->setThirdPartySetting('content_translation', 'translation_sync', $column_settings);
+            }
+            // If the field does not have translatable enabled we need to reset
+            // the sync settings to their defaults.
+            else {
+              $field_config->unsetThirdPartySetting('content_translation', 'translation_sync');
+            }
+            $field_config->save();
+          }
+        }
+      }
     }
   }
 
-  content_translation_save_settings($settings);
+  // Ensure entity and menu router information are correctly rebuilt.
+  \Drupal::entityManager()->clearCachedDefinitions();
+  \Drupal::service('router.builder')->setRebuildNeeded();
+
   drupal_set_message(t('Settings successfully updated.'));
 }
diff --git a/core/modules/content_translation/content_translation.install b/core/modules/content_translation/content_translation.install
index 06a355b..4aa7e73 100644
--- a/core/modules/content_translation/content_translation.install
+++ b/core/modules/content_translation/content_translation.install
@@ -88,19 +88,6 @@ function content_translation_install() {
   // hook_module_implements_alter() is run among the last ones.
   module_set_weight('content_translation', 10);
   \Drupal::service('language_negotiator')->saveConfiguration(LanguageInterface::TYPE_CONTENT, array(LanguageNegotiationUrl::METHOD_ID => 0));
-
-  $config_names = \Drupal::configFactory()->listAll(\Drupal::entityManager()->getDefinition('field_storage_config')->getConfigPrefix() . '.');
-  foreach ($config_names as $name) {
-    \Drupal::config($name)
-      ->set('settings.translation_sync', FALSE)
-      ->save();
-  }
-  $config_names = \Drupal::configFactory()->listAll('field.instance.');
-  foreach ($config_names as $name) {
-    \Drupal::config($name)
-      ->set('settings.translation_sync', FALSE)
-      ->save();
-  }
 }
 
 /**
@@ -118,21 +105,3 @@ function content_translation_enable() {
   $message = t('<a href="!settings_url">Enable translation</a> for <em>content types</em>, <em>taxonomy vocabularies</em>, <em>accounts</em>, or any other element you wish to translate.', $t_args);
   drupal_set_message($message, 'warning');
 }
-
-/**
- * Implements hook_uninstall().
- */
-function content_translation_uninstall() {
-  $config_names = \Drupal::configFactory()->listAll(\Drupal::entityManager()->getDefinition('field_storage_config')->getConfigPrefix() . '.');
-  foreach ($config_names as $name) {
-    \Drupal::config($name)
-      ->clear('settings.translation_sync')
-      ->save();
-  }
-  $config_names = \Drupal::configFactory()->listAll('field.instance.');
-  foreach ($config_names as $name) {
-    \Drupal::config($name)
-      ->clear('settings.translation_sync')
-      ->save();
-  }
-}
diff --git a/core/modules/content_translation/content_translation.module b/core/modules/content_translation/content_translation.module
index d218a8d..72d5bb9 100644
--- a/core/modules/content_translation/content_translation.module
+++ b/core/modules/content_translation/content_translation.module
@@ -642,8 +642,8 @@ function content_translation_form_field_ui_field_instance_edit_form_alter(array
     module_load_include('inc', 'content_translation', 'content_translation.admin');
     $element = content_translation_field_sync_widget($instance);
     if ($element) {
-      $form['instance']['settings']['translation_sync'] = $element;
-      $form['instance']['settings']['translation_sync']['#weight'] = -10;
+      $form['instance']['third_party_settings']['content_translation']['translation_sync'] = $element;
+      $form['instance']['third_party_settings']['content_translation']['translation_sync']['#weight'] = -10;
     }
   }
 }
@@ -652,16 +652,6 @@ function content_translation_form_field_ui_field_instance_edit_form_alter(array
  * Implements hook_entity_presave().
  */
 function content_translation_entity_presave(EntityInterface $entity) {
-  // By default no column has to be synchronized.
-  // @todo Replace with own storage in https://drupal.org/node/2224761
-  if ($entity->getEntityTypeId() === 'field_storage_config') {
-    $entity->settings += array('translation_sync' => FALSE);
-  }
-  // Synchronization can be enabled per instance.
-  // @todo Replace with own storage in https://drupal.org/node/2224761
-  if ($entity->getEntityTypeId() === 'field_instance_config') {
-    $entity->settings += array('translation_sync' => FALSE);
-  }
   if ($entity instanceof ContentEntityInterface && $entity->isTranslatable()) {
     // @todo Avoid using request attributes once translation metadata become
     //   regular fields.
@@ -791,45 +781,3 @@ function content_translation_preprocess_language_content_settings_table(&$variab
   module_load_include('inc', 'content_translation', 'content_translation.admin');
   _content_translation_preprocess_language_content_settings_table($variables);
 }
-
-/**
- * Stores content translation settings.
- *
- * @param array $settings
- *   An associative array of settings keyed by entity type and bundle. At bundle
- *   level the following keys are available:
- *   - translatable: The bundle translatability status, which is a bool.
- *   - columns: An associative array of translation synchronization settings
- *     keyed by field names.
- */
-function content_translation_save_settings($settings) {
-  foreach ($settings as $entity_type => $entity_settings) {
-    foreach ($entity_settings as $bundle => $bundle_settings) {
-      // The 'translatable' value is set only if it is possible to enable.
-      if (isset($bundle_settings['translatable'])) {
-        // Store whether a bundle has translation enabled or not.
-        content_translation_set_config($entity_type, $bundle, 'enabled', $bundle_settings['translatable']);
-
-        // Save translation_sync settings.
-        if (!empty($bundle_settings['columns'])) {
-          foreach ($bundle_settings['columns'] as $field_name => $column_settings) {
-            $instance = FieldInstanceConfig::loadByName($entity_type, $bundle, $field_name);
-            if ($instance->isTranslatable()) {
-              $instance->settings['translation_sync'] = $column_settings;
-            }
-            // If the field does not have translatable enabled we need to reset
-            // the sync settings to their defaults.
-            else {
-              unset($instance->settings['translation_sync']);
-            }
-            $instance->save();
-          }
-        }
-      }
-    }
-  }
-
-  // Ensure entity and menu router information are correctly rebuilt.
-  \Drupal::entityManager()->clearCachedDefinitions();
-  \Drupal::service('router.builder')->setRebuildNeeded();
-}
diff --git a/core/modules/content_translation/src/FieldTranslationSynchronizer.php b/core/modules/content_translation/src/FieldTranslationSynchronizer.php
index 196512b..6715577 100644
--- a/core/modules/content_translation/src/FieldTranslationSynchronizer.php
+++ b/core/modules/content_translation/src/FieldTranslationSynchronizer.php
@@ -7,6 +7,7 @@
 
 namespace Drupal\content_translation;
 
+use Drupal\Core\Config\Entity\ThirdPartySettingsInterface;
 use Drupal\Core\Entity\ContentEntityInterface;
 use Drupal\Core\Entity\EntityInterface;
 use Drupal\Core\Entity\EntityManagerInterface;
@@ -54,6 +55,7 @@ public function synchronizeFields(ContentEntityInterface $entity, $sync_langcode
       return;
     }
 
+    /** @var \Drupal\Core\Field\FieldItemListInterface $items */
     foreach ($entity as $field_name => $items) {
       $field_definition = $items->getFieldDefinition();
       $field_type_definition = $field_type_manager->getDefinition($field_definition->getType());
@@ -61,7 +63,7 @@ public function synchronizeFields(ContentEntityInterface $entity, $sync_langcode
 
       // Sync if the field is translatable, not empty, and the synchronization
       // setting is enabled.
-      if ($field_definition->isTranslatable() && !$items->isEmpty() && $translation_sync = $field_definition->getSetting('translation_sync')) {
+      if ($field_definition instanceof ThirdPartySettingsInterface && $field_definition->isTranslatable() && !$items->isEmpty() && $translation_sync = $field_definition->getThirdPartySetting('content_translation', 'translation_sync')) {
         // Retrieve all the untranslatable column groups and merge them into
         // single list.
         $groups = array_keys(array_diff($translation_sync, array_filter($translation_sync)));
diff --git a/core/modules/content_translation/src/FieldTranslationSynchronizerInterface.php b/core/modules/content_translation/src/FieldTranslationSynchronizerInterface.php
index 0c60b18..0a5f38a 100644
--- a/core/modules/content_translation/src/FieldTranslationSynchronizerInterface.php
+++ b/core/modules/content_translation/src/FieldTranslationSynchronizerInterface.php
@@ -20,7 +20,8 @@
    * Field column synchronization takes care of propagating any change in the
    * field items order and in the column values themselves to all the available
    * translations. This functionality is provided by defining a
-   * 'translation_sync' key in the field instance settings, holding an array of
+   * 'translation_sync' key for the 'content_translation' module's portion of
+   * the field definition's 'third_party_settings', holding an array of
    * column names to be synchronized. The synchronized column values are shared
    * across translations, while the rest varies per-language. This is useful for
    * instance to translate the "alt" and "title" textual elements of an image
diff --git a/core/modules/content_translation/src/Tests/ContentTranslationSyncImageTest.php b/core/modules/content_translation/src/Tests/ContentTranslationSyncImageTest.php
index 98b9540..5783ed8 100644
--- a/core/modules/content_translation/src/Tests/ContentTranslationSyncImageTest.php
+++ b/core/modules/content_translation/src/Tests/ContentTranslationSyncImageTest.php
@@ -62,11 +62,13 @@ protected function setupTestFields() {
       'field_name' => $this->fieldName,
       'bundle' => $this->entityTypeId,
       'label' => 'Test translatable image field',
-      'settings' => array(
-        'translation_sync' => array(
-          'file' => FALSE,
-          'alt' => 'alt',
-          'title' => 'title',
+      'third_party_settings' => array(
+        'content_translation' => array(
+          'translation_sync' => array(
+            'file' => FALSE,
+            'alt' => 'alt',
+            'title' => 'title',
+          ),
         ),
       ),
     ))->save();
@@ -87,11 +89,11 @@ function testImageFieldSync() {
     // Check that the alt and title fields are enabled for the image field.
     $this->drupalLogin($this->editor);
     $this->drupalGet('entity_test_mul/structure/' . $this->entityTypeId . '/fields/' . $this->entityTypeId . '.' . $this->entityTypeId . '.' . $this->fieldName);
-    $this->assertFieldChecked('edit-instance-settings-translation-sync-alt');
-    $this->assertFieldChecked('edit-instance-settings-translation-sync-title');
+    $this->assertFieldChecked('edit-instance-third-party-settings-content-translation-translation-sync-alt');
+    $this->assertFieldChecked('edit-instance-third-party-settings-content-translation-translation-sync-title');
     $edit = array(
-      'instance[settings][translation_sync][alt]' => FALSE,
-      'instance[settings][translation_sync][title]' => FALSE,
+      'instance[third_party_settings][content_translation][translation_sync][alt]' => FALSE,
+      'instance[third_party_settings][content_translation][translation_sync][title]' => FALSE,
     );
     $this->drupalPostForm(NULL, $edit, t('Save settings'));
 
diff --git a/core/modules/field_ui/src/Form/FieldInstanceEditForm.php b/core/modules/field_ui/src/Form/FieldInstanceEditForm.php
index bc72248..dacd4f2 100644
--- a/core/modules/field_ui/src/Form/FieldInstanceEditForm.php
+++ b/core/modules/field_ui/src/Form/FieldInstanceEditForm.php
@@ -186,7 +186,7 @@ public function submitForm(array &$form, FormStateInterface $form_state) {
 
     // Merge incoming values into the instance.
     foreach ($form_state->getValue('instance') as $key => $value) {
-      $this->instance->$key = $value;
+      $this->instance->set($key, $value);
     }
     $this->instance->save();
 
diff --git a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php
index 8a58798..aef8d23 100644
--- a/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php
+++ b/core/tests/Drupal/Tests/Core/Config/Entity/ConfigEntityBaseUnitTest.php
@@ -280,6 +280,18 @@ public function providerCalculateDependenciesWithPluginBags() {
   }
 
   /**
+   * @covers ::calculateDependencies
+   */
+  public function testCalculateDependenciesWithThirdPartySettings() {
+    $this->entity = $this->getMockForAbstractClass('\Drupal\Tests\Core\Config\Entity\Fixtures\ConfigEntityBaseWithThirdPartySettings', array(array(), $this->entityTypeId));
+    $this->entity->setThirdPartySetting('test_provider', 'test', 'test');
+    $this->entity->setThirdPartySetting('test_provider2', 'test', 'test');
+    $this->entity->setThirdPartySetting($this->provider, 'test', 'test');
+
+    $this->assertEquals(array('test_provider', 'test_provider2'), $this->entity->calculateDependencies()['module']);
+  }
+
+  /**
    * @covers ::setOriginalId
    * @covers ::getOriginalId
    */
diff --git a/core/tests/Drupal/Tests/Core/Config/Entity/Fixtures/ConfigEntityBaseWithThirdPartySettings.php b/core/tests/Drupal/Tests/Core/Config/Entity/Fixtures/ConfigEntityBaseWithThirdPartySettings.php
new file mode 100644
index 0000000..9d5db7c
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Config/Entity/Fixtures/ConfigEntityBaseWithThirdPartySettings.php
@@ -0,0 +1,24 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\Config\Entity\Fixtures\ConfigEntityBaseWithThirdPartySettings.
+ */
+
+namespace Drupal\Tests\Core\Config\Entity\Fixtures;
+
+use Drupal\Core\Config\Entity\ConfigEntityBase;
+use Drupal\Core\Config\Entity\ThirdPartySettingsInterface;
+use Drupal\Core\Config\Entity\ThirdPartySettingsTrait;
+
+/**
+ * Enables testing of dependency calculation.
+ *
+ * @see \Drupal\Tests\Core\Config\Entity\ConfigEntityBaseUnitTest::testCalculateDependenciesWithThirdPartySettings()
+ * @see \Drupal\Core\Config\Entity\ConfigEntityBase::calculateDependencies()
+ */
+abstract class ConfigEntityBaseWithThirdPartySettings extends ConfigEntityBase implements ThirdPartySettingsInterface {
+  use ThirdPartySettingsTrait;
+
+  protected $third_party_settings = array();
+}
diff --git a/core/tests/Drupal/Tests/Core/Config/Entity/ThirdPartySettingsTraitTest.php b/core/tests/Drupal/Tests/Core/Config/Entity/ThirdPartySettingsTraitTest.php
new file mode 100644
index 0000000..3d9f8a9
--- /dev/null
+++ b/core/tests/Drupal/Tests/Core/Config/Entity/ThirdPartySettingsTraitTest.php
@@ -0,0 +1,116 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Tests\Core\Config\Entity\ThirdPartySettingsTraitTest.
+ */
+
+namespace Drupal\Tests\Core\Config\Entity;
+
+use Drupal\Core\Config\Entity\ThirdPartySettingsTrait;
+use Drupal\Tests\UnitTestCase;
+
+/**
+ * @coversDefaultClass \Drupal\Core\Config\Entity\ThirdPartySettingsTrait
+ * @group Config
+ */
+class ThirdPartySettingsTraitTest extends UnitTestCase {
+
+  /**
+   * @covers ::getThirdPartySetting
+   * @covers ::setThirdPartySetting
+   * @covers ::unsetThirdPartySetting
+   * @covers ::getThirdPartyProviders
+   *
+   * @dataProvider providerTestThirdPartySettings
+   */
+  public function testThirdPartySettings($third_party_settings_key = NULL) {
+    $key = 'test';
+    $third_party = 'test_provider';
+    $value = $this->getRandomGenerator()->string();
+
+    $trait_object = new TestThirdPartySettingsTrait($third_party_settings_key);
+
+    // Test getThirdPartySetting() with no settings.
+    $this->assertEquals($value, $trait_object->getThirdPartySetting($third_party, $key, $value));
+    $this->assertNull($trait_object->getThirdPartySetting($third_party, $key));
+
+    // Test setThirdPartySetting().
+    $trait_object->setThirdPartySetting($third_party, $key, $value);
+    $this->assertEquals($value, $trait_object->getThirdPartySetting($third_party, $key));
+    $this->assertEquals($value, $trait_object->getThirdPartySetting($third_party, $key, $this->randomGenerator->string()));
+
+    // Test getThirdPartyProviders().
+    $trait_object->setThirdPartySetting('test_provider2', $key, $value);
+    $this->assertEquals(array($third_party, 'test_provider2'), $trait_object->getThirdPartyProviders());
+
+    // Test unsetThirdPartyProviders().
+    $trait_object->unsetThirdPartySetting('test_provider2', $key);
+    $this->assertEquals(array($third_party), $trait_object->getThirdPartyProviders());
+  }
+
+  public function providerTestThirdPartySettings() {
+    return array(array(NULL), array('settings'));
+  }
+
+  /**
+   * @covers ::getThirdPartySetting
+   * @covers ::setThirdPartySetting
+   * @covers ::unsetThirdPartySetting
+   * @covers ::getThirdPartyProviders
+   */
+  public function testThirdPartySettingsException() {
+    $key = 'test';
+    $third_party = 'test_provider';
+    $value = $this->getRandomGenerator()->string();
+
+    $trait_object = new TestThirdPartySettingsTrait('exception');
+    $this->assertEquals('integer', gettype($trait_object->exception));
+
+    // Test getThirdPartySetting() with no settings.
+    try {
+      $trait_object->getThirdPartySetting($third_party, $key, $value);
+      $this->fail('getThirdPartySettings throws no exception when third party storage is not an array.');
+    }
+    catch (\Exception $e) { }
+
+    // Test setThirdPartySetting().
+    try {
+      $trait_object->setThirdPartySetting($third_party, $key, $value);
+      $this->fail('setThirdPartySettings throws no exception when third party storage is not an array.');
+    }
+    catch (\Exception $e) { }
+
+    // Test getThirdPartyProviders().
+    try {
+      $trait_object->getThirdPartyProviders();
+      $this->fail('getThirdPartyProviders throws no exception when third party storage is not an array.');
+    }
+    catch (\Exception $e) { }
+
+    // Test unsetThirdPartyProviders().
+    try {
+      $trait_object->unsetThirdPartySetting('test_provider', $key);
+      $this->fail('unsetThirdPartySetting throws no exception when third party storage is not an array.');
+    }
+    catch (\Exception $e) { }
+  }
+
+}
+
+class TestThirdPartySettingsTrait {
+  use ThirdPartySettingsTrait;
+
+  public function __construct($third_party_settings_key = NULL) {
+    if ($third_party_settings_key) {
+      $this->thirdPartySettingKey = $third_party_settings_key;
+    }
+    if ($third_party_settings_key != 'exception') {
+      $this->{$this->thirdPartySettingKey} = array();
+    }
+    else {
+      $this->{$this->thirdPartySettingKey} = 12;
+    }
+  }
+
+}