Update to Drupal 8.0.0 beta 14. For more information, see https://drupal.org/node/2544542

core/lib/Drupal/Core/Language/ContextProvider/CurrentLanguageContext.php

@@ -0,0 +1,81 @@
+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Language\ContextProvider\CurrentLanguageContext.
+ */
+
+namespace Drupal\Core\Language\ContextProvider;
+
+use Drupal\Core\Cache\CacheableMetadata;
+use Drupal\Core\Language\LanguageManagerInterface;
+use Drupal\Core\Plugin\Context\Context;
+use Drupal\Core\Plugin\Context\ContextDefinition;
+use Drupal\Core\Plugin\Context\ContextProviderInterface;
+use Drupal\Core\StringTranslation\StringTranslationTrait;
+
+/**
+ * Sets the current language as a context.
+ */
+class CurrentLanguageContext implements ContextProviderInterface {
+
+  use StringTranslationTrait;
+
+  /**
+   * The language manager.
+   *
+   * @var \Drupal\Core\Language\LanguageManagerInterface
+   */
+  protected $languageManager;
+
+  /**
+   * Constructs a new CurrentLanguageContext.
+   *
+   * @param \Drupal\Core\Language\LanguageManagerInterface
+   *   The language manager.
+   */
+  public function __construct(LanguageManagerInterface $language_manager) {
+    $this->languageManager = $language_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getRuntimeContexts(array $unqualified_context_ids) {
+    // Add a context for each language type.
+    $language_types = $this->languageManager->getLanguageTypes();
+    $info = $this->languageManager->getDefinedLanguageTypesInfo();
+
+    if ($unqualified_context_ids) {
+      foreach ($unqualified_context_ids as $unqualified_context_id) {
+        if (array_search($unqualified_context_id, $language_types) === FALSE) {
+          unset($language_types[$unqualified_context_id]);
+        }
+      }
+    }
+
+    $result = [];
+    foreach ($language_types as $type_key) {
+      if (isset($info[$type_key]['name'])) {
+        $context = new Context(new ContextDefinition('language', $info[$type_key]['name']));
+        $context->setContextValue($this->languageManager->getCurrentLanguage($type_key));
+
+        $cacheability = new CacheableMetadata();
+        $cacheability->setCacheContexts(['languages:' . $type_key]);
+        $context->addCacheableDependency($cacheability);
+
+        $result[$type_key] = $context;
+      }
+    }
+
+    return $result;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getAvailableContexts() {
+    return $this->getRuntimeContexts([]);
+  }
+
+}

core/lib/Drupal/Core/Language/LanguageManager.php

@@ -87,28 +87,43 @@ class LanguageManager implements LanguageManagerInterface {
   }
 
   /**
-   * {@inheritdoc}
+   * Returns information about all defined language types.
+   *
+   * Defines the three core language types:
+   * - Interface language is the only configurable language type in core. It is
+   *   used by t() as the default language if none is specified.
+   * - Content language is by default non-configurable and inherits the
+   *   interface language negotiated value. It is used by the Field API to
+   *   determine the display language for fields if no explicit value is
+   *   specified.
+   * - URL language is by default non-configurable and is determined through the
+   *   URL language negotiation method or the URL fallback language negotiation
+   *   method if no language can be detected. It is used by l() as the default
+   *   language if none is specified.
+   *
+   * @return array
+   *   An associative array of language type information arrays keyed by
+   *   language type machine name, in the format of
+   *   hook_language_types_info().
    */
   public function getDefinedLanguageTypesInfo() {
-    // This needs to have the same return value as
-    // language_language_type_info(), so that even if the Language module is
-    // not defined, users of this information, such as the Views module, can
-    // access names and descriptions of the default language types.
-    return array(
+    $this->definedLanguageTypesInfo = array(
       LanguageInterface::TYPE_INTERFACE => array(
-        'name' => $this->t('Interface text'),
-        'description' => $this->t('Order of language detection methods for interface text. If a translation of interface text is available in the detected language, it will be displayed.'),
+        'name' => new TranslationWrapper('Interface text'),
+        'description' => new TranslationWrapper('Order of language detection methods for interface text. If a translation of interface text is available in the detected language, it will be displayed.'),
         'locked' => TRUE,
       ),
       LanguageInterface::TYPE_CONTENT => array(
-        'name' => $this->t('Content'),
-        'description' => $this->t('Order of language detection methods for content. If a version of content is available in the detected language, it will be displayed.'),
+        'name' => new TranslationWrapper('Content'),
+        'description' => new TranslationWrapper('Order of language detection methods for content. If a version of content is available in the detected language, it will be displayed.'),
         'locked' => TRUE,
       ),
       LanguageInterface::TYPE_URL => array(
         'locked' => TRUE,
       ),
     );
+
+    return $this->definedLanguageTypesInfo;
   }
 
   /**