diff --git a/core/core.services.yml b/core/core.services.yml
index 60fd6d5..677d21c 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -289,7 +289,7 @@ services:
     arguments: ['@stream_wrapper_manager', '@settings', '@logger.channel.file']
   form_builder:
     class: Drupal\Core\Form\FormBuilder
-    arguments: ['@form_validator', '@form_submitter', '@form_cache', '@module_handler', '@event_dispatcher', '@request_stack', '@class_resolver', '@element_info', '@theme.manager', '@?csrf_token']
+    arguments: ['@form_validator', '@form_submitter', '@form_cache', '@module_handler', '@event_dispatcher', '@request_stack', '@class_resolver', '@element_info', '@theme.manager', '@private_key', '@keyvalue.expirable', '@?csrf_token']
   form_validator:
     class: Drupal\Core\Form\FormValidator
     arguments: ['@request_stack', '@string_translation', '@csrf_token', '@logger.channel.form']
diff --git a/core/lib/Drupal/Core/Form/FormBuilder.php b/core/lib/Drupal/Core/Form/FormBuilder.php
index fa411a2..af408a2 100644
--- a/core/lib/Drupal/Core/Form/FormBuilder.php
+++ b/core/lib/Drupal/Core/Form/FormBuilder.php
@@ -15,6 +15,8 @@
 use Drupal\Core\Access\CsrfTokenGenerator;
 use Drupal\Core\DependencyInjection\ClassResolverInterface;
 use Drupal\Core\Extension\ModuleHandlerInterface;
+use Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface;
+use Drupal\Core\PrivateKey;
 use Drupal\Core\Render\Element;
 use Drupal\Core\Render\ElementInfoManagerInterface;
 use Drupal\Core\Site\Settings;
@@ -104,6 +106,20 @@ class FormBuilder implements FormBuilderInterface, FormValidatorInterface, FormS
   protected $formCache;
 
   /**
+   * The private key service.
+   *
+   * @var \Drupal\Core\PrivateKey
+   */
+  protected $privateKey;
+
+  /**
+   * The expirable key value factory.
+   *
+   * @var \Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface
+   */
+  protected $keyValueExpirableFactory;
+
+  /**
    * Constructs a new FormBuilder.
    *
    * @param \Drupal\Core\Form\FormValidatorInterface $form_validator
@@ -124,10 +140,12 @@ class FormBuilder implements FormBuilderInterface, FormValidatorInterface, FormS
    *   The element info manager.
    * @param \Drupal\Core\Theme\ThemeManagerInterface $theme_manager
    *   The theme manager.
+   * @param \Drupal\Core\PrivateKey $private_key
+   * @param \Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface $key_value_expirable_factory
    * @param \Drupal\Core\Access\CsrfTokenGenerator $csrf_token
    *   The CSRF token generator.
    */
-  public function __construct(FormValidatorInterface $form_validator, FormSubmitterInterface $form_submitter, FormCacheInterface $form_cache, ModuleHandlerInterface $module_handler, EventDispatcherInterface $event_dispatcher, RequestStack $request_stack, ClassResolverInterface $class_resolver, ElementInfoManagerInterface $element_info, ThemeManagerInterface $theme_manager, CsrfTokenGenerator $csrf_token = NULL) {
+  public function __construct(FormValidatorInterface $form_validator, FormSubmitterInterface $form_submitter, FormCacheInterface $form_cache, ModuleHandlerInterface $module_handler, EventDispatcherInterface $event_dispatcher, RequestStack $request_stack, ClassResolverInterface $class_resolver, ElementInfoManagerInterface $element_info, ThemeManagerInterface $theme_manager, PrivateKey $private_key, KeyValueExpirableFactoryInterface $key_value_expirable_factory, CsrfTokenGenerator $csrf_token = NULL) {
     $this->formValidator = $form_validator;
     $this->formSubmitter = $form_submitter;
     $this->formCache = $form_cache;
@@ -136,6 +154,8 @@ public function __construct(FormValidatorInterface $form_validator, FormSubmitte
     $this->requestStack = $request_stack;
     $this->classResolver = $class_resolver;
     $this->elementInfo = $element_info;
+    $this->privateKey = $private_key;
+    $this->keyValueExpirableFactory = $key_value_expirable_factory;
     $this->csrfToken = $csrf_token;
     $this->themeManager = $theme_manager;
   }
@@ -181,10 +201,8 @@ public function getForm($form_arg) {
    */
   public function buildForm($form_id, FormStateInterface &$form_state) {
     // Ensure the form ID is prepared.
-    $private_key = \Drupal::service('private_key');
-    $keyvalue = \Drupal::service('keyvalue.expirable');
-    $form_build_key = 'form_build_key:' . Crypt::hmacBase64(serialize($form_id) . serialize($form_state), 'form_key' . $private_key->get() . Settings::getHashSalt());
-    $keyvalue->get('form_build_key')->setWithExpire($form_build_key, [$form_id, $form_state], 21600);
+    $form_build_key = 'form_build_key:' . Crypt::hmacBase64(serialize($form_id) . serialize($form_state), 'form_key' . $this->privateKey->get() . Settings::getHashSalt());
+    $this->keyValueExpirableFactory->get('form_build_key')->setWithExpire($form_build_key, [$form_id, $form_state], 21600);
     $form_id = $this->getFormId($form_id, $form_state);
 
     $input = $form_state->getUserInput();
diff --git a/core/tests/Drupal/Tests/Core/Form/FormTestBase.php b/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
index 12b3260..8ae2abb 100644
--- a/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
+++ b/core/tests/Drupal/Tests/Core/Form/FormTestBase.php
@@ -13,6 +13,7 @@
 use Drupal\Core\Form\FormState;
 use Drupal\Core\Form\FormStateInterface;
 use Drupal\Core\Session\AccountInterface;
+use Drupal\Core\Site\Settings;
 use Drupal\Tests\UnitTestCase;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\RequestStack;
@@ -133,11 +134,6 @@
   protected $translationManager;
 
   /**
-   * @var \Drupal\Core\DrupalKernelInterface|\PHPUnit_Framework_MockObject_MockObject
-   */
-  protected $kernel;
-
-  /**
    * @var \PHPUnit_Framework_MockObject_MockObject|\Psr\Log\LoggerInterface
    */
   protected $logger;
@@ -149,6 +145,16 @@
    */
   protected $themeManager;
 
+  /**
+   * The expirable key value factory.
+   *
+   * @var \Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
+  protected $keyValueExpirableFactory;
+
+  /**
+   * {@inheritdoc}
+   */
   protected function setUp() {
     $this->moduleHandler = $this->getMock('Drupal\Core\Extension\ModuleHandlerInterface');
 
@@ -172,6 +178,21 @@ protected function setUp() {
       ->disableOriginalConstructor()
       ->getMock();
     $this->account = $this->getMock('Drupal\Core\Session\AccountInterface');
+
+    $form_build_key_store = $this->getMock('Drupal\Core\KeyValueStore\KeyValueStoreExpirableInterface');
+    $this->keyValueExpirableFactory = $this->getMock('Drupal\Core\KeyValueStore\KeyValueExpirableFactoryInterface');
+    $this->keyValueExpirableFactory->expects($this->any())
+      ->method('get')
+      ->with('form_build_key')
+      ->willReturn($form_build_key_store);
+    // Set up the settings singleton.
+    new Settings([
+      'hash_salt' => $this->randomMachineName(),
+    ]);
+    $private_key = $this->getMockBuilder('Drupal\Core\PrivateKey')
+      ->disableOriginalConstructor()
+      ->getMock();
+
     $this->themeManager = $this->getMock('Drupal\Core\Theme\ThemeManagerInterface');
     $this->request = new Request();
     $this->eventDispatcher = $this->getMock('Symfony\Component\EventDispatcher\EventDispatcherInterface');
@@ -188,7 +209,7 @@ protected function setUp() {
       ->getMock();
     $this->root = dirname(dirname(substr(__DIR__, 0, -strlen(__NAMESPACE__))));
 
-    $this->formBuilder = new FormBuilder($this->formValidator, $this->formSubmitter, $this->formCache, $this->moduleHandler, $this->eventDispatcher, $this->requestStack, $this->classResolver, $this->elementInfo, $this->themeManager, $this->csrfToken, $this->kernel);
+    $this->formBuilder = new FormBuilder($this->formValidator, $this->formSubmitter, $this->formCache, $this->moduleHandler, $this->eventDispatcher, $this->requestStack, $this->classResolver, $this->elementInfo, $this->themeManager, $private_key, $this->keyValueExpirableFactory, $this->csrfToken);
   }
 
   /**