diff --git a/core/modules/comment/comment.services.yml b/core/modules/comment/comment.services.yml
index f6d9d84..e4181bd 100644
--- a/core/modules/comment/comment.services.yml
+++ b/core/modules/comment/comment.services.yml
@@ -7,7 +7,7 @@ services:
 
   comment.manager:
     class: Drupal\comment\CommentManager
-    arguments: ['@field.info', '@entity.manager', '@entity.query', '@current_user', '@config.factory', '@string_translation', '@url_generator', '@module_handler']
+    arguments: ['@field.info', '@entity.manager', '@entity.query', '@config.factory', '@string_translation', '@url_generator', '@module_handler']
 
   comment.statistics:
     class: Drupal\comment\CommentStatistics
diff --git a/core/modules/comment/lib/Drupal/comment/CommentManager.php b/core/modules/comment/lib/Drupal/comment/CommentManager.php
index 2f64cac..5a2efe9 100644
--- a/core/modules/comment/lib/Drupal/comment/CommentManager.php
+++ b/core/modules/comment/lib/Drupal/comment/CommentManager.php
@@ -16,6 +16,7 @@
 use Drupal\Core\Extension\ModuleHandlerInterface;
 use Drupal\Core\Routing\UrlGeneratorInterface;
 use Drupal\Core\Session\AccountInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 use Drupal\Core\StringTranslation\TranslationInterface;
 use Drupal\field\FieldInfo;
 
@@ -23,6 +24,7 @@
  * Comment manager contains common functions to manage comment fields.
  */
 class CommentManager implements CommentManagerInterface {
+  use StringTranslationTrait;
 
   /**
    * The field info service.
@@ -46,13 +48,6 @@ class CommentManager implements CommentManagerInterface {
   protected $queryFactory;
 
   /**
-   * The current user.
-   *
-   * @var \Drupal\Core\Session\AccountInterface $current_user
-   */
-  protected $currentUser;
-
-  /**
    * Whether the DRUPAL_AUTHENTICATED_RID can post comments.
    *
    * @var bool
@@ -67,13 +62,6 @@ class CommentManager implements CommentManagerInterface {
   protected $userConfig;
 
   /**
-   * The string translation service.
-   *
-   * @var \Drupal\Core\StringTranslation\TranslationInterface
-   */
-  protected $translationManager;
-
-  /**
    * The url generator service.
    *
    * @var \Drupal\Core\Routing\UrlGeneratorInterface
@@ -96,24 +84,21 @@ class CommentManager implements CommentManagerInterface {
    *   The entity manager service.
    * @param \Drupal\Core\Entity\Query\QueryFactory $query_factory
    *   The entity query factory.
-   * @param \Drupal\Core\Session\AccountInterface $current_user
-   *   The current user.
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
    *   The config factory.
-   * @param \Drupal\Core\StringTranslation\TranslationInterface $translation_manager
+   * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
    *   The string translation service.
    * @param \Drupal\Core\Routing\UrlGeneratorInterface $url_generator
    *   The url generator service.
-   * @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
+   *  @param \Drupal\Core\Extension\ModuleHandlerInterface $module_handler
    *   The module handler service.
    */
-  public function __construct(FieldInfo $field_info, EntityManagerInterface $entity_manager, QueryFactory $query_factory, AccountInterface $current_user, ConfigFactoryInterface $config_factory, TranslationInterface $translation_manager, UrlGeneratorInterface $url_generator, ModuleHandlerInterface $module_handler) {
+  public function __construct(FieldInfo $field_info, EntityManagerInterface $entity_manager, QueryFactory $query_factory, ConfigFactoryInterface $config_factory, TranslationInterface $string_translation, UrlGeneratorInterface $url_generator, ModuleHandlerInterface $module_handler) {
     $this->fieldInfo = $field_info;
     $this->entityManager = $entity_manager;
     $this->queryFactory = $query_factory;
-    $this->currentUser = $current_user;
     $this->userConfig = $config_factory->get('user.settings');
-    $this->translationManager = $translation_manager;
+    $this->stringTranslation = $string_translation;
     $this->urlGenerator = $url_generator;
     $this->moduleHandler = $module_handler;
   }
@@ -121,16 +106,6 @@ public function __construct(FieldInfo $field_info, EntityManagerInterface $entit
   /**
    * {@inheritdoc}
    */
-  public function getParentEntityUri(CommentInterface $comment) {
-    return $this->entityManager
-      ->getStorage($comment->getCommentedEntityTypeId())
-      ->load($comment->getCommentedEntityId())
-      ->urlInfo();
-  }
-
-  /**
-   * {@inheritdoc}
-   */
   public function getFields($entity_type_id) {
     $entity_type = $this->entityManager->getDefinition($entity_type_id);
     if (!$entity_type->isSubclassOf('\Drupal\Core\Entity\ContentEntityInterface')) {
@@ -299,51 +274,49 @@ public function getFieldUIPageTitle($commented_entity_type, $field_name) {
    * {@inheritdoc}
    */
   public function forbiddenMessage(EntityInterface $entity, $field_name) {
-    if ($this->currentUser->isAnonymous()) {
-      if (!isset($this->authenticatedCanPostComments)) {
-        // We only output a link if we are certain that users will get the
-        // permission to post comments by logging in.
-        $this->authenticatedCanPostComments = $this->entityManager
-          ->getStorage('user_role')
-          ->load(DRUPAL_AUTHENTICATED_RID)
-          ->hasPermission('post comments');
-      }
+    if (!isset($this->authenticatedCanPostComments)) {
+      // We only output a link if we are certain that users will get the
+      // permission to post comments by logging in.
+      $this->authenticatedCanPostComments = $this->entityManager
+        ->getStorage('user_role')
+        ->load(DRUPAL_AUTHENTICATED_RID)
+        ->hasPermission('post comments');
+    }
 
-      if ($this->authenticatedCanPostComments) {
-        // We cannot use drupal_get_destination() because these links
-        // sometimes appear on /node and taxonomy listing pages.
-        if ($entity->get($field_name)->getFieldDefinition()->getSetting('form_location') == COMMENT_FORM_SEPARATE_PAGE) {
-          $destination = array('destination' => 'comment/reply/' . $entity->getEntityTypeId() . '/' . $entity->id() . '/' . $field_name . '#comment-form');
-        }
-        else {
-          $destination = array('destination' => $entity->getSystemPath() . '#comment-form');
-        }
+    if ($this->authenticatedCanPostComments) {
+      // We cannot use drupal_get_destination() because these links
+      // sometimes appear on /node and taxonomy listing pages.
+      if ($entity->get($field_name)->getFieldDefinition()->getSetting('form_location') == COMMENT_FORM_SEPARATE_PAGE) {
+        $destination = array('destination' => 'comment/reply/' . $entity->getEntityTypeId() . '/' . $entity->id() . '/' . $field_name . '#comment-form');
+      }
+      else {
+        $destination = array('destination' => $entity->getSystemPath() . '#comment-form');
+      }
 
-        if ($this->userConfig->get('register') != USER_REGISTER_ADMINISTRATORS_ONLY) {
-          // Users can register themselves.
-          return $this->t('<a href="@login">Log in</a> or <a href="@register">register</a> to post comments', array(
-            '@login' => $this->urlGenerator->generateFromRoute('user.login', array(), array('query' => $destination)),
-            '@register' => $this->urlGenerator->generateFromRoute('user.register', array(), array('query' => $destination)),
-          ));
-        }
-        else {
-          // Only admins can add new users, no public registration.
-          return $this->t('<a href="@login">Log in</a> to post comments', array(
-            '@login' => $this->urlGenerator->generateFromRoute('user.login', array(), array('query' => $destination)),
-          ));
-        }
+      if ($this->userConfig->get('register') != USER_REGISTER_ADMINISTRATORS_ONLY) {
+        // Users can register themselves.
+        return $this->t('<a href="@login">Log in</a> or <a href="@register">register</a> to post comments', array(
+          '@login' => $this->urlGenerator->generateFromRoute('user.login', array(), array('query' => $destination)),
+          '@register' => $this->urlGenerator->generateFromRoute('user.register', array(), array('query' => $destination)),
+        ));
+      }
+      else {
+        // Only admins can add new users, no public registration.
+        return $this->t('<a href="@login">Log in</a> to post comments', array(
+          '@login' => $this->urlGenerator->generateFromRoute('user.login', array(), array('query' => $destination)),
+        ));
       }
     }
     return '';
   }
 
-  /**
+  /*
    * {@inheritdoc}
    */
-  public function getCountNewComments(EntityInterface $entity, $field_name = NULL, $timestamp = 0) {
+  public function getCountNewComments(EntityInterface $entity, AccountInterface $account, $field_name = NULL, $timestamp = 0) {
     // @todo Replace module handler with optional history service injection
     //   after http://drupal.org/node/2081585
-    if ($this->currentUser->isAuthenticated() && $this->moduleHandler->moduleExists('history')) {
+    if ($account->isAuthenticated() && $this->moduleHandler->moduleExists('history')) {
       // Retrieve the timestamp at which the current user last viewed this entity.
       if (!$timestamp) {
         if ($entity->getEntityTypeId() == 'node') {
@@ -378,14 +351,4 @@ public function getCountNewComments(EntityInterface $entity, $field_name = NULL,
     }
     return FALSE;
   }
-
-  /**
-   * Translates a string to the current language or to a given language.
-   *
-   * See the t() documentation for details.
-   */
-  protected function t($string, array $args = array(), array $options = array()) {
-    return $this->translationManager->translate($string, $args, $options);
-  }
-
 }
diff --git a/core/modules/forum/lib/Drupal/forum/ForumManager.php b/core/modules/forum/lib/Drupal/forum/ForumManager.php
index cababf8..2cf3d11 100644
--- a/core/modules/forum/lib/Drupal/forum/ForumManager.php
+++ b/core/modules/forum/lib/Drupal/forum/ForumManager.php
@@ -13,6 +13,7 @@
 use Drupal\Core\Entity\EntityManagerInterface;
 use Drupal\Core\Session\AccountInterface;
 use Drupal\Core\StringTranslation\TranslationInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
 use Drupal\comment\CommentInterface;
 use Drupal\comment\CommentManagerInterface;
 use Drupal\field\FieldInfo;
@@ -22,6 +23,7 @@
  * Provides forum manager service.
  */
 class ForumManager extends DependencySerialization implements ForumManagerInterface {
+  use StringTranslationTrait;
 
   /**
    * Forum sort order, newest first.
@@ -114,13 +116,6 @@ class ForumManager extends DependencySerialization implements ForumManagerInterf
   protected $fieldInfo;
 
   /**
-   * Translation manager service.
-   *
-   * @var \Drupal\Core\StringTranslation\TranslationInterface
-   */
-  protected $translationManager;
-
-  /**
    * Constructs the forum manager service.
    *
    * @param \Drupal\Core\Config\ConfigFactoryInterface $config_factory
@@ -131,17 +126,17 @@ class ForumManager extends DependencySerialization implements ForumManagerInterf
    *   The current database connection.
    * @param \Drupal\field\FieldInfo $field_info
    *   The field info service.
-   * @param \Drupal\Core\StringTranslation\TranslationInterface $translation_manager
+   * @param \Drupal\Core\StringTranslation\TranslationInterface $string_translation
    *   The translation manager service.
    * @param \Drupal\comment\CommentManagerInterface $comment_manager
    *   The comment manager service.
    */
-  public function __construct(ConfigFactoryInterface $config_factory, EntityManagerInterface $entity_manager, Connection $connection, FieldInfo $field_info, TranslationInterface $translation_manager, CommentManagerInterface $comment_manager) {
+  public function __construct(ConfigFactoryInterface $config_factory, EntityManagerInterface $entity_manager, Connection $connection, FieldInfo $field_info, TranslationInterface $string_translation, CommentManagerInterface $comment_manager) {
     $this->configFactory = $config_factory;
     $this->entityManager = $entity_manager;
     $this->connection = $connection;
     $this->fieldInfo = $field_info;
-    $this->translationManager = $translation_manager;
+    $this->stringTranslation = $string_translation;
     $this->commentManager = $comment_manager;
   }
 
@@ -547,15 +542,6 @@ public function updateIndex($nid) {
   }
 
   /**
-   * Translates a string to the current language or to a given language.
-   *
-   * See the t() documentation for details.
-   */
-  protected function t($string, array $args = array(), array $options = array()) {
-    return $this->translationManager->translate($string, $args, $options);
-  }
-
-  /**
    * {@inheritdoc}
    */
   public function __sleep() {