New TranslationWrapper class to allow string translation to be deferred

Introduced \Drupal\Core\StringTranslation\TranslationWrapper class to wrap translatable strings.

This class delays translating so that circular dependencies in info hooks and early use of annotations can be avoided. \Drupal\Core\Annotation\Translation::get() returns an instance of TranslationWrapper instead of a translated string.

This class is useful for using string translation in very low level subsystems like entity definition, stream wrappers, and annotations.

Drupal 7

 function locale_stream_wrappers() {
   $wrappers = array(
     'translations' => array(
      'name' => t('Translation files'),
       'class' => 'Drupal\locale\TranslationsStream',
      'description' => t('Translation files'),
       'type' => STREAM_WRAPPERS_LOCAL_HIDDEN,
     ),
   );

Drupal 8

 function locale_stream_wrappers() {
   $wrappers = array(
     'translations' => array(
      'name' => new TranslationWrapper('Translation files'),
       'class' => 'Drupal\locale\TranslationsStream',
      'description' => new TranslationWrapper('Translation files'),
       'type' => STREAM_WRAPPERS_LOCAL_HIDDEN,
     ),
   );