diff --git a/core/includes/menu.inc b/core/includes/menu.inc
index d7da9cc..e4015d5 100644
--- a/core/includes/menu.inc
+++ b/core/includes/menu.inc
@@ -322,206 +322,6 @@ function _menu_link_translate(&$item) {
 }
 
 /**
- * Renders a menu tree based on the current path.
- *
- * @param $menu_name
- *   The name of the menu.
- *
- * @return
- *   A structured array representing the specified menu on the current page, to
- *   be rendered by drupal_render().
- */
-function menu_tree($menu_name) {
-  return \Drupal::service('menu_link.tree')->getRenderedTree($menu_name);
-}
-
-/**
- * Returns a rendered menu tree.
- *
- * The menu item's LI element is given one of the following classes:
- * - expanded: The menu item is showing its submenu.
- * - collapsed: The menu item has a submenu which is not shown.
- * - leaf: The menu item has no submenu.
- *
- * @param $tree
- *   A data structure representing the tree as returned from menu_tree_data.
- *
- * @return
- *   A structured array to be rendered by drupal_render().
- */
-function menu_tree_output($tree) {
-  return \Drupal::service('menu_link.tree')->output($tree);
-}
-
-/**
- * Gets the data structure representing a named menu tree.
- *
- * Since this can be the full tree including hidden items, the data returned
- * may be used for generating an an admin interface or a select.
- *
- * @param $menu_name
- *   The named menu links to return
- * @param $link
- *   A fully loaded menu link, or NULL. If a link is supplied, only the
- *   path to root will be included in the returned tree - as if this link
- *   represented the current page in a visible menu.
- * @param $max_depth
- *   Optional maximum depth of links to retrieve. Typically useful if only one
- *   or two levels of a sub tree are needed in conjunction with a non-NULL
- *   $link, in which case $max_depth should be greater than $link['depth'].
- *
- * @return
- *   An tree of menu links in an array, in the order they should be rendered.
- */
-function menu_tree_all_data($menu_name, $link = NULL, $max_depth = NULL) {
-  return \Drupal::service('menu_link.tree')->buildAllData($menu_name, $link, $max_depth);
-}
-
-/**
- * Sets the path for determining the active trail of the specified menu tree.
- *
- * This path will also affect the breadcrumbs under some circumstances.
- * Breadcrumbs are built using the preferred link returned by
- * menu_link_get_preferred(). If the preferred link is inside one of the menus
- * specified in calls to menu_tree_set_path(), the preferred link will be
- * overridden by the corresponding path returned by menu_tree_get_path().
- *
- * Setting this path does not affect the main content; for that use
- * menu_set_active_item() instead.
- *
- * @param $menu_name
- *   The name of the affected menu tree.
- * @param $path
- *   The path to use when finding the active trail.
- */
-function menu_tree_set_path($menu_name, $path = NULL) {
-  return \Drupal::service('menu_link.tree')->setPath($menu_name, $path);
-}
-
-/**
- * Gets the path for determining the active trail of the specified menu tree.
- *
- * @param $menu_name
- *   The menu name of the requested tree.
- *
- * @return
- *   A string containing the path. If no path has been specified with
- *   menu_tree_set_path(), NULL is returned.
- */
-function menu_tree_get_path($menu_name) {
-  return \Drupal::service('menu_link.tree')->getPath($menu_name);
-}
-
-/**
- * Gets the data structure for a named menu tree, based on the current page.
- *
- * The tree order is maintained by storing each parent in an individual
- * field, see http://drupal.org/node/141866 for more.
- *
- * @param $menu_name
- *   The named menu links to return.
- * @param $max_depth
- *   (optional) The maximum depth of links to retrieve.
- * @param $only_active_trail
- *   (optional) Whether to only return the links in the active trail (TRUE)
- *   instead of all links on every level of the menu link tree (FALSE). Defaults
- *   to FALSE.
- *
- * @return
- *   An array of menu links, in the order they should be rendered. The array
- *   is a list of associative arrays -- these have two keys, link and below.
- *   link is a menu item, ready for theming as a link. Below represents the
- *   submenu below the link if there is one, and it is a subtree that has the
- *   same structure described for the top-level array.
- */
-function menu_tree_page_data($menu_name, $max_depth = NULL, $only_active_trail = FALSE) {
-  return \Drupal::service('menu_link.tree')->buildPageData($menu_name, $max_depth, $only_active_trail);
-}
-
-/**
- * Builds a menu tree, translates links, and checks access.
- *
- * @param $menu_name
- *   The name of the menu.
- * @param $parameters
- *   (optional) An associative array of build parameters. Possible keys:
- *   - expanded: An array of parent link ids to return only menu links that are
- *     children of one of the plids in this list. If empty, the whole menu tree
- *     is built, unless 'only_active_trail' is TRUE.
- *   - active_trail: An array of mlids, representing the coordinates of the
- *     currently active menu link.
- *   - only_active_trail: Whether to only return links that are in the active
- *     trail. This option is ignored, if 'expanded' is non-empty.
- *   - min_depth: The minimum depth of menu links in the resulting tree.
- *     Defaults to 1, which is the default to build a whole tree for a menu
- *     (excluding menu container itself).
- *   - max_depth: The maximum depth of menu links in the resulting tree.
- *   - conditions: An associative array of custom database select query
- *     condition key/value pairs; see _menu_build_tree() for the actual query.
- *
- * @return
- *   A fully built menu tree.
- */
-function menu_build_tree($menu_name, array $parameters = array()) {
-  return \Drupal::service('menu_link.tree')->buildTree($menu_name, $parameters);
-}
-
-/**
- * Collects node links from a given menu tree recursively.
- *
- * @param $tree
- *   The menu tree you wish to collect node links from.
- * @param $node_links
- *   An array in which to store the collected node links.
- */
-function menu_tree_collect_node_links(&$tree, &$node_links) {
-  return \Drupal::service('menu_link.tree')->collectNodeLinks($tree, $node_links);
-}
-
-/**
- * Checks access and performs dynamic operations for each link in the tree.
- *
- * @param $tree
- *   The menu tree you wish to operate on.
- * @param $node_links
- *   A collection of node link references generated from $tree by
- *   menu_tree_collect_node_links().
- */
-function menu_tree_check_access(&$tree, $node_links = array()) {
-  return \Drupal::service('menu_link.tree')->checkAccess($tree, $node_links);
-}
-
-/**
- * Sorts and returns the built data representing a menu tree.
- *
- * @param $links
- *   A flat array of menu links that are part of the menu. Each array element
- *   is an associative array of information about the menu link, containing the
- *   fields from the {menu_links} table, and optionally additional information
- *   from the {menu_router} table, if the menu item appears in both tables.
- *   This array must be ordered depth-first. See _menu_build_tree() for a sample
- *   query.
- * @param $parents
- *   An array of the menu link ID values that are in the path from the current
- *   page to the root of the menu tree.
- * @param $depth
- *   The minimum depth to include in the returned menu tree.
- *
- * @return
- *   An array of menu links in the form of a tree. Each item in the tree is an
- *   associative array containing:
- *   - link: The menu link item from $links, with additional element
- *     'in_active_trail' (TRUE if the link ID was in $parents).
- *   - below: An array containing the sub-tree of this item, where each element
- *     is a tree item array with 'link' and 'below' elements. This array will be
- *     empty if the menu item has no items in its sub-tree having a depth
- *     greater than or equal to $depth.
- */
-function menu_tree_data(array $links, array $parents = array(), $depth = 1) {
-  return \Drupal::service('menu_link.tree')->buildTreeData($links, $parents, $depth);
-}
-
-/**
  * Implements template_preprocess_HOOK() for theme_menu_tree().
  */
 function template_preprocess_menu_tree(&$variables) {
@@ -724,7 +524,9 @@ function menu_navigation_links($menu_name, $level = 0) {
   }
 
   // Get the menu hierarchy for the current page.
-  $tree = menu_tree_page_data($menu_name, $level + 1);
+    /** @var \Drupal\menu_link\MenuTreeInterface $menu_tree */
+  $menu_tree = \Drupal::service('menu_link.tree');
+  $tree = $menu_tree->buildPageData($menu_name, $level + 1);
 
   // Go down the active trail until the right level is reached.
   while ($level-- > 0 && $tree) {
@@ -973,6 +775,9 @@ function menu_set_active_item($path) {
 function menu_set_active_trail($new_trail = NULL) {
   $trail = &drupal_static(__FUNCTION__);
 
+  /** @var \Drupal\menu_link\MenuTreeInterface $menu_tree */
+  $menu_tree = \Drupal::service('menu_link.tree');
+
   if (isset($new_trail)) {
     $trail = $new_trail;
   }
@@ -996,7 +801,7 @@ function menu_set_active_trail($new_trail = NULL) {
       // Pass TRUE for $only_active_trail to make menu_tree_page_data() build
       // a stripped down menu tree containing the active trail only, in case
       // the given menu has not been built in this request yet.
-      $tree = menu_tree_page_data($preferred_link['menu_name'], NULL, TRUE);
+      $tree = $menu_tree->buildPageData($preferred_link['menu_name'], NULL, TRUE);
       list($key, $curr) = each($tree);
     }
     // There is no link for the current path.
diff --git a/core/modules/menu/lib/Drupal/menu/MenuFormController.php b/core/modules/menu/lib/Drupal/menu/MenuFormController.php
index d6720a7..67803f3 100644
--- a/core/modules/menu/lib/Drupal/menu/MenuFormController.php
+++ b/core/modules/menu/lib/Drupal/menu/MenuFormController.php
@@ -12,6 +12,7 @@
 use Drupal\Core\Entity\Query\QueryFactory;
 use Drupal\Core\Language\Language;
 use Drupal\menu_link\MenuLinkStorageControllerInterface;
+use Drupal\menu_link\MenuTreeInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
@@ -34,6 +35,13 @@ class MenuFormController extends EntityFormController {
   protected $menuLinkStorage;
 
   /**
+   * The menu tree.
+   *
+   * @var \Drupal\menu_link\MenuTreeInterface
+   */
+  protected $menuTree;
+
+  /**
    * The overview tree form.
    *
    * @var array
@@ -47,10 +55,13 @@ class MenuFormController extends EntityFormController {
    *   The factory for entity queries.
    * @param \Drupal\menu_link\MenuLinkStorageControllerInterface $menu_link_storage
    *   The menu link storage controller.
+   * @param \Drupal\menu_link\MenuTreeInterface $menu_tree
+   *   The menu tree.
    */
-  public function __construct(QueryFactory $entity_query_factory, MenuLinkStorageControllerInterface $menu_link_storage) {
+  public function __construct(QueryFactory $entity_query_factory, MenuLinkStorageControllerInterface $menu_link_storage, MenuTreeInterface $menu_tree) {
     $this->entityQueryFactory = $entity_query_factory;
     $this->menuLinkStorage = $menu_link_storage;
+    $this->menuTree = $menu_tree;
   }
 
   /**
@@ -59,7 +70,8 @@ public function __construct(QueryFactory $entity_query_factory, MenuLinkStorageC
   public static function create(ContainerInterface $container) {
     return new static(
       $container->get('entity.query'),
-      $container->get('entity.manager')->getStorageController('menu_link')
+      $container->get('entity.manager')->getStorageController('menu_link'),
+      $container->get('menu_link.tree')
     );
   }
 
@@ -256,13 +268,13 @@ protected function buildOverviewForm(array &$form, array &$form_state) {
     }
 
     $delta = max(count($links), 50);
-    $tree = menu_tree_data($links);
+    $tree = $this->menuTree->buildTreeData($links);
     $node_links = array();
-    menu_tree_collect_node_links($tree, $node_links);
+    $this->menuTree->collectNodeLinks($tree, $node_links);
 
     // We indicate that a menu administrator is running the menu access check.
     $this->getRequest()->attributes->set('_menu_admin', TRUE);
-    menu_tree_check_access($tree, $node_links);
+    $this->menuTree->checkAccess($tree, $node_links);
     $this->getRequest()->attributes->set('_menu_admin', FALSE);
 
     $form = array_merge($form, $this->buildOverviewTreeForm($tree, $delta));
diff --git a/core/modules/menu/menu.module b/core/modules/menu/menu.module
index 8eb1d34..786dd93 100644
--- a/core/modules/menu/menu.module
+++ b/core/modules/menu/menu.module
@@ -263,10 +263,13 @@ function _menu_get_options($menus, $available_menus, $item) {
     $limit = _menu_parent_depth_limit($item);
   }
 
+    /** @var \Drupal\menu_link\MenuTreeInterface $menu_tree */
+  $menu_tree = \Drupal::service('menu_link.tree');
+
   $options = array();
   foreach ($menus as $menu_name => $title) {
     if (isset($available_menus[$menu_name])) {
-      $tree = menu_tree_all_data($menu_name, NULL);
+      $tree = $menu_tree->buildAllData($menu_name, NULL);
       $options[$menu_name . ':0'] = '<' . $title . '>';
       _menu_parents_recurse($tree, $menu_name, '--', $options, $item['mlid'], $limit);
     }
diff --git a/core/modules/menu_link/lib/Drupal/menu_link/MenuTree.php b/core/modules/menu_link/lib/Drupal/menu_link/MenuTree.php
index c2b574f..7060e35 100644
--- a/core/modules/menu_link/lib/Drupal/menu_link/MenuTree.php
+++ b/core/modules/menu_link/lib/Drupal/menu_link/MenuTree.php
@@ -147,9 +147,11 @@ public function __construct(Connection $database, CacheBackendInterface $cache_b
   public function buildAllData($menu_name, $link = NULL, $max_depth = NULL) {
     $language_interface = $this->languageManager->getCurrentLanguage();
 
-    // Use $mlid as a flag for whether the data being loaded is for the whole tree.
+    // Use $mlid as a flag for whether the data being loaded is for the whole
+    // tree.
     $mlid = isset($link['mlid']) ? $link['mlid'] : 0;
-    // Generate a cache ID (cid) specific for this $menu_name, $link, $language, and depth.
+    // Generate a cache ID (cid) specific for this $menu_name, $link, $language,
+    // and depth.
     $cid = 'links:' . $menu_name . ':all:' . $mlid . ':' . $language_interface->id . ':' . (int) $max_depth;
 
     if (!isset($this->menuFullTrees[$cid])) {
@@ -167,8 +169,9 @@ public function buildAllData($menu_name, $link = NULL, $max_depth = NULL) {
           'max_depth' => $max_depth,
         );
         if ($mlid) {
-          // The tree is for a single item, so we need to match the values in its
-          // p columns and 0 (the top level) with the plid values of other links.
+          // The tree is for a single item, so we need to match the values in
+          // its p columns and 0 (the top level) with the plid values of other
+          // links.
           $parents = array(0);
           for ($i = 1; $i < MENU_MAX_DEPTH; $i++) {
             if (!empty($link["p$i"])) {
@@ -220,8 +223,8 @@ public function buildPageData($menu_name, $max_depth = NULL, $only_active_trail
       // won't be built anymore, as this function is invoked from
       // template_preprocess_page(). So in order to not build a giant menu tree
       // that needs to be checked for access on all levels, we simply check
-      // whether we have the menu already in cache, or otherwise, build a minimum
-      // tree containing the active trail only.
+      // whether we have the menu already in cache, or otherwise, build a
+      // minimum tree containing the active trail only.
       // @see menu_set_active_trail()
       if (!isset($this->menuPageTrees[$cid]) && $only_active_trail) {
         $cid .= ':trail';
@@ -248,22 +251,23 @@ public function buildPageData($menu_name, $max_depth = NULL, $only_active_trail
           // If this page is accessible to the current user, build the tree
           // parameters accordingly.
           if ($page_not_403) {
-            // Find a menu link corresponding to the current path. If $active_path
-            // is NULL, let menu_link_get_preferred() determine the path.
+            // Find a menu link corresponding to the current path. If
+            // $active_path is NULL, let menu_link_get_preferred() determine
+            // the path.
             if ($active_link = $this->menuLinkGetPreferred($menu_name, $active_path)) {
               // The active link may only be taken into account to build the
-              // active trail, if it resides in the requested menu. Otherwise,
-              // we'd needlessly re-run _menu_build_tree() queries for every menu
-              // on every page.
+              // active trail, if it resides in the requested menu.
+              // Otherwise, we'd needlessly re-run _menu_build_tree() queries
+              // for every menu on every page.
               if ($active_link['menu_name'] == $menu_name) {
-                // Use all the coordinates, except the last one because there
-                // can be no child beyond the last column.
+                // Use all the coordinates, except the last one because
+                // there can be no child beyond the last column.
                 for ($i = 1; $i < MENU_MAX_DEPTH; $i++) {
                   if ($active_link['p' . $i]) {
                     $active_trail[$active_link['p' . $i]] = $active_link['p' . $i];
                   }
                 }
-                // If we are asked to build links for the active trail only, skip
+                // If we are asked to build links for the active trail only,skip
                 // the entire 'expanded' handling.
                 if ($only_active_trail) {
                   $tree_parameters['only_active_trail'] = TRUE;
@@ -300,8 +304,8 @@ public function buildPageData($menu_name, $max_depth = NULL, $only_active_trail
           $this->cache->set($cid, $tree_parameters, Cache::PERMANENT, array('menu' => $menu_name));
         }
 
-        // Build the tree using the parameters; the resulting tree will be cached
-        // by _menu_build_tree().
+        // Build the tree using the parameters; the resulting tree will be
+        // cached by $tihs->buildTree().
         $this->menuPageTrees[$cid] = $this->buildTree($menu_name, $tree_parameters);
       }
       return $this->menuPageTrees[$cid];
@@ -418,6 +422,11 @@ public function buildTree($menu_name, array $parameters = array()) {
    * to further massage the data manually before further processing happens.
    * menu_tree_check_access() needs to be invoked afterwards.
    *
+   * @param string $menu_name
+   *   The name of the menu.
+   * @param array $parameters
+   *   The parameters passed into static::buildTree()
+   *
    * @see static::buildTree()
    */
   protected function doBuildTree($menu_name, array $parameters = array()) {
@@ -540,6 +549,9 @@ protected function checkNodeLinksAccess(array $node_links) {
 
   /**
    * Sorts the menu tree and recursively checks access for each item.
+   *
+   * @param array $tree
+   *   The menu tree you wish to operate on.
    */
   protected function doCheckAccess(&$tree) {
     $new_tree = array();
@@ -551,8 +563,9 @@ protected function doCheckAccess(&$tree) {
           $this->doCheckAccess($tree[$key]['below']);
         }
         // The weights are made a uniform 5 digits by adding 50000 as an offset.
-        // After _menu_link_translate(), $item['title'] has the localized link title.
-        // Adding the mlid to the end of the index insures that it is unique.
+        // After _menu_link_translate(), $item['title'] has the localized link
+        // title. Adding the mlid to the end of the index insures that it is
+        // unique.
         $new_tree[(50000 + $item['weight']) . ' ' . $item['title'] . ' ' . $item['mlid']] = $tree[$key];
       }
     }
@@ -575,6 +588,21 @@ public function buildTreeData(array $links, array $parents = array(), $depth = 1
    *
    * The function is a bit complex because the rendering of a link depends on
    * the next menu link.
+   *
+   * @param array $links
+   *   A flat array of menu links that are part of the menu. Each array element
+   *   is an associative array of information about the menu link, containing the
+   *   fields from the {menu_links} table, and optionally additional information
+   *   from the {menu_router} table, if the menu item appears in both tables.
+   *   This array must be ordered depth-first. See _menu_build_tree() for a sample
+   *   query.
+   * @param array $parents
+   *   An array of the menu link ID values that are in the path from the current
+   *   page to the root of the menu tree.
+   * @param int $depth
+   *   The minimum depth to include in the returned menu tree.
+   *
+   * @return array
    */
   protected function doBuildTreeData(&$links, $parents, $depth) {
     $tree = array();
@@ -587,8 +615,9 @@ protected function doBuildTreeData(&$links, $parents, $depth) {
         'link' => $item,
         'below' => array(),
       );
-      // Look ahead to the next link, but leave it on the array so it's available
-      // to other recursive function calls if we return or build a sub-tree.
+      // Look ahead to the next link, but leave it on the array so it's
+      // available to other recursive function calls if we return or build a
+      // sub-tree.
       $next = end($links);
       // Check whether the next link is the first in a new sub-tree.
       if ($next && $next['depth'] > $depth) {
diff --git a/core/modules/menu_link/lib/Drupal/menu_link/MenuTreeInterface.php b/core/modules/menu_link/lib/Drupal/menu_link/MenuTreeInterface.php
index f73b466..29cee05 100644
--- a/core/modules/menu_link/lib/Drupal/menu_link/MenuTreeInterface.php
+++ b/core/modules/menu_link/lib/Drupal/menu_link/MenuTreeInterface.php
@@ -40,9 +40,9 @@ public function output($tree);
    * Setting this path does not affect the main content; for that use
    * menu_set_active_item() instead.
    *
-   * @param $menu_name
+   * @param string $menu_name
    *   The name of the affected menu tree.
-   * @param $path
+   * @param string $path
    *   The path to use when finding the active trail.
    */
   public function setPath($menu_name, $path = NULL);
@@ -50,9 +50,9 @@ public function setPath($menu_name, $path = NULL);
   /**
    * Checks access and performs dynamic operations for each link in the tree.
    *
-   * @param $tree
+   * @param array $tree
    *   The menu tree you wish to operate on.
-   * @param $node_links
+   * @param array $node_links
    *   A collection of node link references generated from $tree by
    *   menu_tree_collect_node_links().
    */
@@ -61,12 +61,12 @@ public function checkAccess(&$tree, $node_links = array());
   /**
    * Gets the path for determining the active trail of the specified menu tree.
    *
-   * @param $menu_name
+   * @param string $menu_name
    *   The menu name of the requested tree.
    *
-   * @return
+   * @return string
    *   A string containing the path. If no path has been specified with
-   *   menu_tree_set_path(), NULL is returned.
+   *   static::setPath(), NULL is returned.
    */
   public function getPath($menu_name);
 
@@ -125,9 +125,9 @@ public function buildPageData($menu_name, $max_depth = NULL, $only_active_trail
   /**
    * Collects node links from a given menu tree recursively.
    *
-   * @param $tree
+   * @param array $tree
    *   The menu tree you wish to collect node links from.
-   * @param $node_links
+   * @param array $node_links
    *   An array in which to store the collected node links.
    */
   public function collectNodeLinks(&$tree, &$node_links);
diff --git a/core/modules/menu_link/tests/Drupal/menu_link/Tests/MenuTreeTest.php b/core/modules/menu_link/tests/Drupal/menu_link/Tests/MenuTreeTest.php
index 901a8d7..0c39171 100644
--- a/core/modules/menu_link/tests/Drupal/menu_link/Tests/MenuTreeTest.php
+++ b/core/modules/menu_link/tests/Drupal/menu_link/Tests/MenuTreeTest.php
@@ -28,12 +28,53 @@ class MenuTreeTest extends UnitTestCase {
    */
   protected $menuTree;
 
+  /**
+   * The mocked database connection.
+   *
+   * @var \Drupal\Core\DatabaseConnection|\PHPUnit_Framework_MockObject_MockObject
+   */
   protected $connection;
+
+  /**
+   * The mocked cache backend.
+   *
+   * @var \Drupal\Core\Cache\CacheBackendInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
   protected $cacheBackend;
+
+  /**
+   * The mocked language manager.
+   *
+   * @var \Drupal\Core\Language\LanguageManagerInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
   protected $languageManager;
+
+  /**
+   * The test request stack.
+   *
+   * @var \Symfony\Component\HttpFoundation\RequestStack.
+   */
   protected $requestStack;
+
+  /**
+   * The mocked entity manager.
+   *
+   * @var \Drupal\Core\Entity\EntityManagerInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
   protected $entityManager;
+
+  /**
+   * The mocked entity query factor.y
+   *
+   * @var  \Drupal\Core\Entity\Query\QueryFactory|\PHPUnit_Framework_MockObject_MockObject
+   */
   protected $entityQueryFactory;
+
+  /**
+   * The mocked state.
+   *
+   * @var \Drupal\Core\KeyValueStore\StateInterface|\PHPUnit_Framework_MockObject_MockObject
+   */
   protected $state;
 
   /**
@@ -330,12 +371,18 @@ class TestMenuTree extends MenuTree {
    */
   public $menuLinkTranslateCallable;
 
+  /**
+   * {@inheritdoc}
+   */
   protected function menuLinkTranslate(&$item) {
     if (isset($this->menuLinkTranslateCallable)) {
       call_user_func_array($this->menuLinkTranslateCallable, array(&$item));
     }
   }
 
+  /**
+   * {@inheritdoc}
+   */
   protected function menuLinkGetPreferred($menu_name, $active_path) {
   }
 
diff --git a/core/modules/shortcut/shortcut.module b/core/modules/shortcut/shortcut.module
index a97b447..93fa4b2 100644
--- a/core/modules/shortcut/shortcut.module
+++ b/core/modules/shortcut/shortcut.module
@@ -314,8 +314,6 @@ function shortcut_valid_link($path) {
  *
  * @return \Drupal\shortcut\ShortcutInterface[]
  *   An array of shortcut links, in the format returned by the menu system.
- *
- * @see menu_tree()
  */
 function shortcut_renderable_links($shortcut_set = NULL) {
   $shortcut_links = array();
diff --git a/core/modules/system/lib/Drupal/system/Plugin/Block/SystemMenuBlock.php b/core/modules/system/lib/Drupal/system/Plugin/Block/SystemMenuBlock.php
index 8298193..3b919ae 100644
--- a/core/modules/system/lib/Drupal/system/Plugin/Block/SystemMenuBlock.php
+++ b/core/modules/system/lib/Drupal/system/Plugin/Block/SystemMenuBlock.php
@@ -8,7 +8,10 @@
 namespace Drupal\system\Plugin\Block;
 
 use Drupal\block\BlockBase;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
 use Drupal\Core\Session\AccountInterface;
+use Drupal\menu_link\MenuTreeInterface;
+use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
  * Provides a generic Menu block.
@@ -20,14 +23,43 @@
  *   derivative = "Drupal\system\Plugin\Derivative\SystemMenuBlock"
  * )
  */
-class SystemMenuBlock extends BlockBase {
+class SystemMenuBlock extends BlockBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The menu tree.
+   *
+   * @var \Drupal\menu_link\MenuTreeInterface
+   */
+  protected $menuTree;
+
+  /**
+   * Constructs a new SystemMenuBlock.
+   *
+   * @param \Drupal\menu_link\MenuTreeInterface $menu_tree
+   *   The menu tree.
+   */
+  public function __construct(MenuTreeInterface $menu_tree) {
+    $this->menuTree = $menu_tree;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, array $plugin_definition) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $container->get('menu_link.tree')
+    );
+  }
 
   /**
    * {@inheritdoc}
    */
   public function build() {
     $menu = $this->getDerivativeId();
-    return menu_tree($menu);
+    return $this->menuTree->getRenderedTree($menu);
   }
 
 }
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 08e6382..1c8a295 100644
--- a/core/modules/system/tests/modules/menu_test/menu_test.module
+++ b/core/modules/system/tests/modules/menu_test/menu_test.module
@@ -219,8 +219,10 @@ function menu_test_callback() {
  */
 function menu_test_menu_trail_callback() {
   $menu_path = \Drupal::state()->get('menu_test.menu_tree_set_path') ?: array();
+  /** @var \Drupal\menu_link\MenuTreeInterface $menu_tree */
+  $menu_tree = \Drupal::service('menu_link.tree');
   if (!empty($menu_path)) {
-    menu_tree_set_path($menu_path['menu_name'], $menu_path['path']);
+    $menu_tree->setPath($menu_path['menu_name'], $menu_path['path']);
   }
   return 'This is menu_test_menu_trail_callback().';
 }
diff --git a/core/modules/toolbar/toolbar.module b/core/modules/toolbar/toolbar.module
index 7217986..ff0bf64 100644
--- a/core/modules/toolbar/toolbar.module
+++ b/core/modules/toolbar/toolbar.module
@@ -358,6 +358,9 @@ function toolbar_toolbar() {
   // Add attributes to the links before rendering.
   toolbar_menu_navigation_links($tree);
 
+    /** @var \Drupal\menu_link\MenuTreeInterface $menu_tree */
+  $menu_tree = \Drupal::service('menu_link.tree');
+
   $menu = array(
     '#heading' => t('Administration menu'),
     'toolbar_administration' => array(
@@ -365,7 +368,7 @@ function toolbar_toolbar() {
       '#attributes' => array(
         'class' => array('toolbar-menu-administration'),
       ),
-      'administration_menu' => menu_tree_output($tree),
+      'administration_menu' => $menu_tree->output($tree),
     ),
   );
 
@@ -417,6 +420,8 @@ function toolbar_toolbar() {
  */
 function toolbar_get_menu_tree() {
   $tree = array();
+  /** @var \Drupal\menu_link\MenuTreeInterface $menu_tree */
+  $menu_tree = \Drupal::service('menu_link.tree');
   $query = \Drupal::entityQuery('menu_link')
     ->condition('menu_name', 'admin')
     ->condition('module', 'system')
@@ -424,7 +429,7 @@ function toolbar_get_menu_tree() {
   $result = $query->execute();
   if (!empty($result)) {
     $admin_link = menu_link_load(reset($result));
-    $tree = menu_build_tree('admin', array(
+    $tree = $menu_tree->buildTree('admin', array(
       'expanded' => array($admin_link['mlid']),
       'min_depth' => $admin_link['depth'] + 1,
       'max_depth' => $admin_link['depth'] + 1,
@@ -467,6 +472,8 @@ function toolbar_menu_navigation_links(&$tree) {
  */
 function toolbar_get_rendered_subtrees() {
   $subtrees = array();
+  /** @var \Drupal\menu_link\MenuTreeInterface $menu_tree */
+  $menu_tree = \Drupal::service('menu_link.tree');
   $tree = toolbar_get_menu_tree();
   foreach ($tree as $tree_item) {
     $item = $tree_item['link'];
@@ -479,9 +486,9 @@ function toolbar_get_rendered_subtrees() {
           $query->condition('p' . $i, $item['p' . $i]);
         }
         $parents = $query->execute()->fetchCol();
-        $subtree = menu_build_tree($item['menu_name'], array('expanded' => $parents, 'min_depth' => $item['depth']+1));
+        $subtree = $menu_tree->buildTreeData($item['menu_name'], array('expanded' => $parents, 'min_depth' => $item['depth']+1));
         toolbar_menu_navigation_links($subtree);
-        $subtree = menu_tree_output($subtree);
+        $subtree = $menu_tree->output($subtree);
         $subtree = drupal_render($subtree);
       }
       else {
diff --git a/core/modules/user/lib/Drupal/user/Tests/UserAccountLinksTests.php b/core/modules/user/lib/Drupal/user/Tests/UserAccountLinksTests.php
index bbe5a71..c9dcd30 100644
--- a/core/modules/user/lib/Drupal/user/Tests/UserAccountLinksTests.php
+++ b/core/modules/user/lib/Drupal/user/Tests/UserAccountLinksTests.php
@@ -67,7 +67,9 @@ function testSecondaryMenu() {
     $this->drupalGet('<front>');
 
     // For a logged-out user, expect no secondary links.
-    $tree = menu_build_tree('account');
+    /** @var \Drupal\menu_link\MenuTreeInterface $menu_tree */
+    $menu_tree = \Drupal::service('menu_link.tree');
+    $tree = $menu_tree->buildTree('account');
     $this->assertEqual(count($tree), 1, 'The secondary links menu contains only one menu link.');
     $link = reset($tree);
     $link = $link['link'];