diff --git a/core/includes/menu.inc b/core/includes/menu.inc
index c8fddcd..27196d1 100644
--- a/core/includes/menu.inc
+++ b/core/includes/menu.inc
@@ -1994,14 +1994,15 @@ function menu_local_tasks($level = 0) {
 
     // If we failed to fetch a router item or the current user doesn't have
     // access to it, don't bother computing the tabs.
-    if (!$router_item || !$router_item['access']) {
+    if ((!$route_name && !$router_item) || ($router_item && !$router_item['access'])) {
       return $empty;
     }
+
     // @todo remove all code using {menu_router} and anything using MENU_*
     // constants when all local actions and local tasks are converted to
     // plugins. The remaining code should just invoke those managers plus do the
     // invocations of hook_menu_local_tasks() and hook_menu_local_tasks_alter().
-
+    if ($router_item) {
     // Get all tabs (also known as local tasks) and the root page.
     $result = db_select('menu_router', NULL, array('fetch' => PDO::FETCH_ASSOC))
       ->fields('menu_router')
@@ -2170,15 +2171,16 @@ function menu_local_tasks($level = 0) {
     // Remove the depth, we are interested only in their relative placement.
     $tabs = array_values($tabs);
     $data['tabs'] += $tabs;
+    }
 
     // Allow modules to dynamically add further tasks.
     $module_handler = \Drupal::moduleHandler();
     foreach ($module_handler->getImplementations('menu_local_tasks') as $module) {
       $function = $module . '_menu_local_tasks';
-      $function($data, $router_item, $root_path);
+      $function($data, $route_name);
     }
     // Allow modules to alter local tasks.
-    $module_handler->alter('menu_local_tasks', $data, $router_item, $root_path);
+    $module_handler->alter('menu_local_tasks', $data, $route_name);
   }
 
   if (isset($data['tabs'][$level])) {
diff --git a/core/modules/block/custom_block/custom_block.module b/core/modules/block/custom_block/custom_block.module
index eed50a4..8e81778 100644
--- a/core/modules/block/custom_block/custom_block.module
+++ b/core/modules/block/custom_block/custom_block.module
@@ -30,8 +30,8 @@ function custom_block_help($path, $arg) {
 /**
  * Implements hook_menu_local_tasks().
  */
-function custom_block_menu_local_tasks(&$data, $router_item, $root_path) {
-  if ($router_item['route_name'] == 'custom_block.list') {
+function custom_block_menu_local_tasks(&$data, $route_name) {
+  if ($route_name == 'custom_block.list') {
     // @todo Move to a LocalAction plugin when https://drupal.org/node/2045267
     //   allows local actions to work with query strings.
     $item = menu_get_item('block/add');
@@ -48,13 +48,13 @@ function custom_block_menu_local_tasks(&$data, $router_item, $root_path) {
   $routes = array_map(function ($theme) {
     return "block.admin_display_$theme";
   }, array_keys(list_themes()));
-  if (in_array($router_item['route_name'], $routes)) {
+  if (in_array($route_name, $routes)) {
     // @todo Move to a LocalAction plugin when https://drupal.org/node/2045267
     //   allows local actions to work with query strings.
     $item = menu_get_item('block/add');
     if ($item['access']) {
       // Add a destination parameter.
-      $item['localized_options']['query']['theme'] = end($router_item['map']);
+      $item['localized_options']['query']['theme'] = \Drupal::request()->attributes->get('theme');
       $data['actions']['block/add'] = array(
         '#theme' => 'menu_local_action',
         '#link' => $item,
diff --git a/core/modules/forum/forum.module b/core/modules/forum/forum.module
index 090d593..d43552a 100644
--- a/core/modules/forum/forum.module
+++ b/core/modules/forum/forum.module
@@ -148,11 +148,11 @@ function forum_menu() {
 /**
  * Implements hook_menu_local_tasks().
  */
-function forum_menu_local_tasks(&$data, $router_item, $root_path) {
+function forum_menu_local_tasks(&$data, $route_name) {
   global $user;
 
   // Add action link to 'node/add/forum' on 'forum' sub-pages.
-  if ($root_path == 'forum' || $root_path == 'forum/%') {
+  if (in_array($route_name, array('forum.index', 'forum.page'))) {
     $request = \Drupal::request();
     $forum_term = $request->attributes->get('taxonomy_term');
     $vid = \Drupal::config('forum.settings')->get('vocabulary');
diff --git a/core/modules/node/node.module b/core/modules/node/node.module
index 0dcda45..eaa388e 100644
--- a/core/modules/node/node.module
+++ b/core/modules/node/node.module
@@ -1062,9 +1062,10 @@ function node_menu() {
 /**
  * Implements hook_menu_local_tasks().
  */
-function node_menu_local_tasks(&$data, $router_item, $root_path) {
+function node_menu_local_tasks(&$data, $route_name) {
   // Add action link to 'node/add' on 'admin/content' page.
-  if ($root_path == 'admin/content') {
+  // @todo Switch to inspecting route name in https://drupal.org/node/2021161.
+  if (current_path() == 'admin/content') {
     $item = menu_get_item('node/add');
     if ($item['access']) {
       $data['actions'][] = array(
diff --git a/core/modules/system/system.api.php b/core/modules/system/system.api.php
index f2b0116..d5c1d38 100644
--- a/core/modules/system/system.api.php
+++ b/core/modules/system/system.api.php
@@ -858,12 +858,10 @@ function hook_menu_alter(&$items) {
  *     associative array as described above.
  *   - tabs: A list of (up to 2) tab levels that contain a list of of tabs keyed
  *     by their href, each one being an associative array as described above.
- * @param array $router_item
- *   The menu system router item of the page.
- * @param string $root_path
- *   The path to the root item for this set of tabs.
+ * @param string $route_name
+ *   The route name of the page.
  */
-function hook_menu_local_tasks(&$data, $router_item, $root_path) {
+function hook_menu_local_tasks(&$data, $route_name) {
   // Add an action linking to node/add to all pages.
   $data['actions']['node/add'] = array(
     '#theme' => 'menu_local_action',
@@ -890,8 +888,6 @@ function hook_menu_local_tasks(&$data, $router_item, $root_path) {
         ),
       ),
     ),
-    // Define whether this link is active. This can usually be omitted.
-    '#active' => ($router_item['path'] == $root_path),
   );
 }
 
@@ -904,14 +900,12 @@ function hook_menu_local_tasks(&$data, $router_item, $root_path) {
  * @param array $data
  *   An associative array containing tabs and actions. See
  *   hook_menu_local_tasks() for details.
- * @param array $router_item
- *   The menu system router item of the page.
- * @param string $root_path
- *   The path to the root item for this set of tabs.
+ * @param string $route_name
+ *   The route name of the page.
  *
  * @see hook_menu_local_tasks()
  */
-function hook_menu_local_tasks_alter(&$data, $router_item, $root_path) {
+function hook_menu_local_tasks_alter(&$data, $route_name) {
 }
 
 /**
diff --git a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/Routing/RouteSubscriber.php b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/Routing/RouteSubscriber.php
index 6e10a3c..8834b4a 100644
--- a/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/Routing/RouteSubscriber.php
+++ b/core/modules/system/tests/modules/entity_test/lib/Drupal/entity_test/Routing/RouteSubscriber.php
@@ -30,7 +30,10 @@ public static function getSubscribedEvents() {
    */
   public function routes(RouteBuildEvent $event) {
     $collection = $event->getRouteCollection();
-    foreach (entity_test_entity_types() as $entity_type) {
+    $types = entity_test_entity_types();
+    $types[] = 'entity_test_render';
+
+    foreach ($types as $entity_type) {
       $route = new Route(
         "$entity_type/add",
         array('_content' => '\Drupal\entity_test\Controller\EntityTestController::testAdd', 'entity_type' => $entity_type),
diff --git a/core/modules/system/tests/modules/menu_test/menu_test.local_tasks.yml b/core/modules/system/tests/modules/menu_test/menu_test.local_tasks.yml
index 7d270f3..02ce8f2 100644
--- a/core/modules/system/tests/modules/menu_test/menu_test.local_tasks.yml
+++ b/core/modules/system/tests/modules/menu_test/menu_test.local_tasks.yml
@@ -52,3 +52,22 @@ menu_local_task_test_upcasting_sub2:
   title: 'upcasting sub2'
   tab_root_id: menu_local_task_test_upcasting_sub1
   weight: 10
+
+menu_test.tasks_default_tab:
+  route_name: menu_test.tasks_default
+  title: 'View'
+  tab_root_id: menu_test.tasks_default_tab
+
+menu_test.tasks_tasks_tab:
+  route_name: menu_test.tasks_tasks
+  title: 'View'
+  tab_root_id: menu_test.tasks_tasks_tab
+menu_test.tasks_edit_tab:
+  route_name: menu_test.tasks_edit
+  title: 'Edit'
+  tab_root_id: menu_test.tasks_tasks_tab
+menu_test.tasks_settings_tab:
+  route_name: menu_test.tasks_settings
+  title: 'Settings'
+  weight: 100
+  tab_root_id: menu_test.tasks_tasks_tab
diff --git a/core/modules/system/tests/modules/menu_test/menu_test.module b/core/modules/system/tests/modules/menu_test/menu_test.module
index c75b1c7..566a620 100644
--- a/core/modules/system/tests/modules/menu_test/menu_test.module
+++ b/core/modules/system/tests/modules/menu_test/menu_test.module
@@ -226,29 +226,10 @@ function menu_test_menu() {
     'title' => 'Default only',
     'route_name' => 'menu_test.tasks_default',
   );
-  $items['menu-test/tasks/default/view'] = array(
-    'title' => 'View',
-    'type' => MENU_DEFAULT_LOCAL_TASK,
-  );
   $items['menu-test/tasks/tasks'] = array(
     'title' => 'With tasks',
     'route_name' => 'menu_test.tasks_tasks',
   );
-  $items['menu-test/tasks/tasks/view'] = array(
-    'title' => 'View',
-    'type' => MENU_DEFAULT_LOCAL_TASK,
-  );
-  $items['menu-test/tasks/tasks/edit'] = array(
-    'title' => 'Edit',
-    'type' => MENU_LOCAL_TASK,
-    'route_name' => 'menu_test.tasks_edit',
-  );
-  $items['menu-test/tasks/tasks/settings'] = array(
-    'title' => 'Settings',
-    'type' => MENU_LOCAL_TASK,
-    'weight' => 100,
-    'route_name' => 'menu_test.tasks_settings',
-  );
 
   // Menu trail tests.
   // @see MenuTrailTestCase
@@ -364,11 +345,11 @@ function menu_test_local_action_dynamic_title($arg) {
  * If the menu_test.settings configuration 'tasks.add' has been set, adds
  * several local tasks to menu-test/tasks.
  */
-function menu_test_menu_local_tasks(&$data, $router_item, $root_path) {
+function menu_test_menu_local_tasks(&$data, $route_name) {
   if (!\Drupal::config('menu_test.settings')->get('tasks.add')) {
     return;
   }
-  if (strpos($router_item['tab_root'], 'menu-test/tasks/') === 0) {
+  if (in_array($route_name, array('menu_test.tasks_default', 'menu_test.tasks_empty', 'menu_test.tasks_tasks'))) {
     $data['tabs'][0]['foo'] = array(
       '#theme' => 'menu_local_task',
       '#link' => array(
@@ -394,17 +375,17 @@ function menu_test_menu_local_tasks(&$data, $router_item, $root_path) {
  * If the menu_test.settings configuration 'tasks.alter' has been set, adds
  * several local tasks to menu-test/tasks.
  */
-function menu_test_menu_local_tasks_alter(&$data, $router_item, $root_path) {
+function menu_test_menu_local_tasks_alter(&$data, $route_name) {
   if (!\Drupal::config('menu_test.settings')->get('tasks.alter')) {
     return;
   }
-  if (strpos($router_item['tab_root'], 'menu-test/tasks/') === 0) {
+  if (in_array($route_name, array('menu_test.tasks_default', 'menu_test.tasks_empty', 'menu_test.tasks_tasks'))) {
     // Rename the default local task from 'View' to 'Show'.
     // $data['tabs'] is expected to be keyed by link hrefs.
     // The default local task always links to its parent path, which means that
     // if the tab root path appears as key in $data['tabs'], then that key is
     // the default local task.
-    $key = $router_item['tab_root'];
+    $key = $route_name . '_tab';
     if (isset($data['tabs'][0][$key])) {
       $data['tabs'][0][$key]['#link']['title'] = 'Show it';
     }