diff --git a/core/core.services.yml b/core/core.services.yml
index 224222b..6568923 100644
--- a/core/core.services.yml
+++ b/core/core.services.yml
@@ -665,6 +665,8 @@ services:
   theme.initialisation:
     class: Drupal\Core\Theme\Initialisation
     arguments: ['@theme_handler', '@theme.negotiator']
+    calls:
+      - [setRequest, ['@?request=']]
   theme.registry:
     class: Drupal\Core\Theme\Registry
     arguments: ['@cache.cache', '@lock', '@module_handler']
diff --git a/core/lib/Drupal/Core/Theme/DefaultNegotiator.php b/core/lib/Drupal/Core/Theme/DefaultNegotiator.php
index b08882d..94dc4e6 100644
--- a/core/lib/Drupal/Core/Theme/DefaultNegotiator.php
+++ b/core/lib/Drupal/Core/Theme/DefaultNegotiator.php
@@ -16,11 +16,11 @@
 class DefaultNegotiator implements ThemeNegotiatorInterface {
 
   /**
-   * The system theme config object.
+   * The config factory
    *
-   * @var \Drupal\Core\Config\Config
+   * @var \Drupal\Core\Config\ConfigFactory
    */
-  protected $config;
+  protected $configFactory;
 
   /**
    * Constructs a DefaultNegotiator object.
@@ -29,7 +29,7 @@ class DefaultNegotiator implements ThemeNegotiatorInterface {
    *   The config factory.
    */
   public function __construct(ConfigFactory $config_factory) {
-    $this->config = $config_factory->get('system.theme');
+    $this->configFactory = $config_factory;
   }
 
   /**
@@ -43,7 +43,7 @@ public function applies(Request $request) {
    * {@inheritdoc}
    */
   public function determineActiveTheme(Request $request) {
-    return $this->config->get('default');
+    return $this->configFactory->get('system.theme')->get('default');
   }
 
 }
diff --git a/core/lib/Drupal/Core/Theme/Initialisation.php b/core/lib/Drupal/Core/Theme/Initialisation.php
index 53a4c09..688c4b4 100644
--- a/core/lib/Drupal/Core/Theme/Initialisation.php
+++ b/core/lib/Drupal/Core/Theme/Initialisation.php
@@ -8,15 +8,57 @@
 namespace Drupal\Core\Theme;
 
 use Drupal\Core\Extension\ThemeHandlerInterface;
+use Symfony\Component\HttpFoundation\Request;
 
+/**
+ * Provides the theme initialisation logic.
+ */
 class Initialisation {
 
+  /**
+   * The theme handler.
+   *
+   * @var \Drupal\Core\Extension\ThemeHandlerInterface
+   */
+  protected $themeHandler;
 
+  /**
+   * The theme negotiator.
+   *
+   * @var \Drupal\Core\Theme\ThemeNegotiator
+   */
+  protected $themeNegotiator;
+
+  /**
+   * The current request.
+   *
+   * @var \Symfony\Component\HttpFoundation\Request
+   */
+  protected $request;
+
+  /**
+   * Constructs a new Initialisation instance.
+   *
+   * @param \Drupal\Core\Extension\ThemeHandlerInterface $theme_handler
+   *   The theme handler.
+   * @param \Drupal\Core\Theme\ThemeNegotiator $theme_negotiator
+   *   The theme negotiator.
+   */
   public function __construct(ThemeHandlerInterface $theme_handler, ThemeNegotiator $theme_negotiator) {
     $this->themeHandler = $theme_handler;
     $this->themeNegotiator = $theme_negotiator;
   }
 
+  /**
+   * Sets the current theme.
+   *
+   * @param \Symfony\Component\HttpFoundation\Request $request
+   *   The current request.
+   */
+  public function setRequest(Request $request) {
+    $this->request = $request;
+  }
+
   public function initThemeSystem() {
     global $theme, $theme_key;
 
@@ -30,8 +72,7 @@ public function initThemeSystem() {
     // @todo Let the theme.negotiator listen to the kernel request event.
     // Determine the active theme for the theme negotiator service. This includes
     // the default theme as well as really specific ones like the ajax base theme.
-    $request = \Drupal::request();
-    $theme = $this->themeNegotiator->determineActiveTheme($request) ?: 'stark';
+    $theme = $this->themeNegotiator->determineActiveTheme($this->request) ?: 'stark';
 
     // Store the identifier for retrieving theme settings with.
     $theme_key = $theme;
@@ -225,4 +266,4 @@ public function loadIncludes($theme, $base_theme) {
     return $theme_engine;
   }
 
-} 
+}