commit 4c1b20aa60f53c66de883afbc3bedeb31b718930
Author: Karoly Negyesi <chx1975@gmail.com>
Date:   Thu Mar 31 14:20:14 2016 -0700

    add <nolink> support

diff --git a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
index 9c97caa..20797f5 100644
--- a/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
+++ b/core/modules/link/src/Plugin/Field/FieldWidget/LinkWidget.php
@@ -82,6 +82,9 @@ protected static function getUriAsDisplayableString($uri) {
         $displayable_string = EntityAutocomplete::getEntityLabels(array($entity));
       }
     }
+    elseif ($uri == 'route:<nolink>') {
+      $displayable_string = '<nolink>';
+    }
 
     return $displayable_string;
   }
@@ -114,6 +117,9 @@ protected static function getUserEnteredStringAsUri($string) {
       //    https://www.drupal.org/node/2423093.
       $uri = 'entity:node/' . $entity_id;
     }
+    elseif ($string == '<nolink>') {
+      $uri = 'route:<nolink>';
+    }
     // Detect a schemeless string, map to 'internal:' URI.
     elseif (!empty($string) && parse_url($string, PHP_URL_SCHEME) === NULL) {
       // @todo '<front>' is valid input for BC reasons, may be removed by