Issue #2914595 by _gradient_: \Drupal\Core\Theme\ThemeInitialization declares...

Issue #2914595 by _gradient_: \Drupal\Core\Theme\ThemeInitialization declares $moduleHandler dynamically

core/lib/Drupal/Core/Theme/ThemeInitialization.php

@@ -40,6 +40,13 @@ class ThemeInitialization implements ThemeInitializationInterface {
    */
   protected $extensions;
 
+  /**
+   * The module handler.
+   *
+   * @var \Drupal\Core\Extension\ModuleHandlerInterface
+   */
+  protected $moduleHandler;
+
   /**
    * Constructs a new ThemeInitialization object.
    *