4 files changed, 53 insertions, 30 deletions
diff --git a/core/modules/toolbar/src/Hook/ToolbarThemeHooks.php b/core/modules/toolbar/src/Hook/ToolbarThemeHooks.php
new file mode 100644
index 00000000000..fb08f0ffde6
--- /dev/null
+++ b/core/modules/toolbar/src/Hook/ToolbarThemeHooks.php
@@ -0,0 +1,23 @@
+<?php
+
+namespace Drupal\toolbar\Hook;
+
+use Drupal\Core\Hook\Attribute\Hook;
+
+/**
+ * Hook implementations for toolbar.
+ */
+class ToolbarThemeHooks {
+
+  /**
+   * Implements hook_preprocess_HOOK() for HTML document templates.
+   */
+  #[Hook('preprocess_html')]
+  public function preprocessHtml(&$variables): void {
+    if (!\Drupal::currentUser()->hasPermission('access toolbar')) {
+      return;
+    }
+    $variables['attributes']['class'][] = 'toolbar-loading';
+  }
+
+}
diff --git a/core/modules/toolbar/tests/modules/toolbar_test/src/Hook/ToolbarTestThemeHooks.php b/core/modules/toolbar/tests/modules/toolbar_test/src/Hook/ToolbarTestThemeHooks.php
new file mode 100644
index 00000000000..e1d40c8219a
--- /dev/null
+++ b/core/modules/toolbar/tests/modules/toolbar_test/src/Hook/ToolbarTestThemeHooks.php
@@ -0,0 +1,30 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Drupal\toolbar_test\Hook;
+
+use Drupal\Core\Hook\Attribute\Hook;
+
+/**
+ * Hook implementations for toolbar_test.
+ */
+class ToolbarTestThemeHooks {
+
+  /**
+   * Implements hook_preprocess_HOOK().
+   */
+  #[Hook('preprocess_menu')]
+  public function preprocessMenu(&$variables): void {
+    // All the standard hook_theme variables should be populated when the
+    // Toolbar module is rendering a menu.
+    foreach ([
+      'menu_name',
+      'items',
+      'attributes',
+    ] as $variable) {
+      $variables[$variable];
+    }
+  }
+
+}
diff --git a/core/modules/toolbar/tests/modules/toolbar_test/toolbar_test.module b/core/modules/toolbar/tests/modules/toolbar_test/toolbar_test.module
deleted file mode 100644
index 8980eb4a6ef..00000000000
--- a/core/modules/toolbar/tests/modules/toolbar_test/toolbar_test.module
+++ /dev/null
@@ -1,19 +0,0 @@
-<?php
-
-/**
- * @file
- * A dummy module to test API interaction with the Toolbar module.
- */
-
-declare(strict_types=1);
-
-/**
- * Implements hook_preprocess_HOOK().
- */
-function toolbar_test_preprocess_menu(&$variables): void {
-  // All the standard hook_theme variables should be populated when the
-  // Toolbar module is rendering a menu.
-  foreach (['menu_name', 'items', 'attributes'] as $variable) {
-    $variables[$variable];
-  }
-}
diff --git a/core/modules/toolbar/toolbar.module b/core/modules/toolbar/toolbar.module
index 51986310901..4bfcd89e187 100644
--- a/core/modules/toolbar/toolbar.module
+++ b/core/modules/toolbar/toolbar.module
@@ -118,17 +118,6 @@ function toolbar_menu_navigation_links(array $tree) {
 }
 
 /**
- * Implements hook_preprocess_HOOK() for HTML document templates.
- */
-function toolbar_preprocess_html(&$variables): void {
-  if (!\Drupal::currentUser()->hasPermission('access toolbar')) {
-    return;
-  }
-
-  $variables['attributes']['class'][] = 'toolbar-loading';
-}
-
-/**
  * Returns the rendered subtree of each top-level toolbar link.
  *
  * @return array