diff --git a/core/lib/Drupal/Core/Menu/LocalTaskManager.php b/core/lib/Drupal/Core/Menu/LocalTaskManager.php
index 6aa0ffd..8b36395 100644
--- a/core/lib/Drupal/Core/Menu/LocalTaskManager.php
+++ b/core/lib/Drupal/Core/Menu/LocalTaskManager.php
@@ -208,14 +208,7 @@ public function getLocalTasksForRoute($route_name) {
         $children = $cache->data['children'];
       }
       else {
-        $definitions = $this->getDefinitions();
-        // We build the hierarchy by finding all tabs that should
-        // appear on the current route.
-        list($definitions, $base_routes, $parents) = $this->calculateHierarchyTaskInformation($route_name, $definitions);
-        $children = array();
-        if ($base_routes) {
-          $children = $this->findBaseRouteChildren($definitions, $base_routes, $parents);
-        }
+        list ($base_routes, $parents, $children) = $this->calculateLocalTasksInformationForRoute($route_name);
         $this->setLocalTasksCache($route_name, $base_routes, $parents, $children);
       }
 
@@ -225,6 +218,28 @@ public function getLocalTasksForRoute($route_name) {
   }
 
   /**
+   * Find all local tasks that appear on a named route.
+   *
+   * @param string $route_name
+   *   The route for which to find local tasks.
+   *
+   * @return array
+   *   An array with the matching base routes, parents and children.
+   */
+  protected function calculateLocalTasksInformationForRoute($route_name) {
+    $definitions = $this->getDefinitions();
+    // We build the hierarchy by finding all tabs that should
+    // appear on the current route.
+    list($definitions, $base_routes, $parents) = $this->calculateHierarchyTaskInformation($route_name, $definitions);
+    $children = array();
+    if ($base_routes) {
+      $children = $this->findBaseRouteChildren($definitions, $base_routes, $parents);
+    }
+
+    return [$base_routes, $parents, $children];
+  }
+
+  /**
    * {@inheritdoc}
    */
   public function getTasksBuild($current_route_name, RefinableCacheableDependencyInterface &$cacheability) {
@@ -368,13 +383,15 @@ protected function isRouteActive($current_route_name, $route_name, $route_parame
    *   An array of plugin information keyed by parent ID and plugin ID.
    */
   protected function findBaseRouteChildren(array $definitions, array $base_routes, array $parents) {
+    $active_local_task_definitions = array_filter($definitions, function ($task_info) {
+      return !empty($base_routes[$task_info['base_route']]) && (empty($task_info['parent_id']) || !empty($parents[$task_info['parent_id']]));
+    });
+
     $children = [];
-    foreach ($definitions as $plugin_id => $task_info) {
-      if (!empty($base_routes[$task_info['base_route']]) && (empty($task_info['parent_id']) || !empty($parents[$task_info['parent_id']]))) {
-        // Concat '> ' with root ID for the parent of top-level tabs.
-        $parent = empty($task_info['parent_id']) ? '> ' . $task_info['base_route'] : $task_info['parent_id'];
-        $children[$parent][$plugin_id] = $task_info;
-      }
+    foreach ($active_local_task_definitions as $plugin_id => $task_info) {
+      // Concat '> ' with root ID for the parent of top-level tabs.
+      $parent = empty($task_info['parent_id']) ? '> ' . $task_info['base_route'] : $task_info['parent_id'];
+      $children[$parent][$plugin_id] = $task_info;
     }
     return $children;
   }