diff --git a/core/lib/Drupal/Core/Routing/UrlGenerator.php b/core/lib/Drupal/Core/Routing/UrlGenerator.php
index 5a58722..6bc12b0 100644
--- a/core/lib/Drupal/Core/Routing/UrlGenerator.php
+++ b/core/lib/Drupal/Core/Routing/UrlGenerator.php
@@ -75,17 +75,15 @@ class UrlGenerator implements UrlGeneratorInterface {
    * @param \Symfony\Component\HttpFoundation\RequestStack $request_stack
    *   A request stack object.
    * @param string[] $filter_protocols
-   *   An array of protocols allowed for URL generation.
+   *   (optional) An array of protocols allowed for URL generation.
    */
-  public function __construct(RouteProviderInterface $provider, OutboundPathProcessorInterface $path_processor, OutboundRouteProcessorInterface $route_processor, RequestStack $request_stack, $filter_protocols) {
+  public function __construct(RouteProviderInterface $provider, OutboundPathProcessorInterface $path_processor, OutboundRouteProcessorInterface $route_processor, RequestStack $request_stack, array $filter_protocols = ['http', 'https']) {
     $this->provider = $provider;
     $this->context = new RequestContext();
 
     $this->pathProcessor = $path_processor;
     $this->routeProcessor = $route_processor;
-    // Ensure to have a safe fallback. This is also needed for some tests, which
-    // don't specify the filter protocols container parameter.
-    UrlHelper::setAllowedProtocols($filter_protocols ?: ['http', 'https']);
+    UrlHelper::setAllowedProtocols($filter_protocols);
     $this->requestStack = $request_stack;
   }
 
diff --git a/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php b/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php
index b9e729a..1e807b3 100644
--- a/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php
+++ b/core/lib/Drupal/Core/Utility/UnroutedUrlAssembler.php
@@ -43,12 +43,10 @@ class UnroutedUrlAssembler implements UnroutedUrlAssemblerInterface {
    * @param \Drupal\Core\PathProcessor\OutboundPathProcessorInterface $path_processor
    *   The output path processor.
    * @param string[] $filter_protocols
-   *   An array of protocols allowed for URL generation.
+   *   (optional) An array of protocols allowed for URL generation.
    */
-  public function __construct(RequestStack $request_stack, OutboundPathProcessorInterface $path_processor, $filter_protocols = []) {
-    // Ensure to have a safe fallback. This is also needed for some tests, which
-    // don't specify the filter protocols container parameter.
-    UrlHelper::setAllowedProtocols($filter_protocols ?: ['http', 'https']);
+  public function __construct(RequestStack $request_stack, OutboundPathProcessorInterface $path_processor, array $filter_protocols = ['http', 'https']) {
+    UrlHelper::setAllowedProtocols($filter_protocols);
     $this->requestStack = $request_stack;
     $this->pathProcessor = $path_processor;
   }