Issue 4580 - Replace ext.i18n.getMessage with i18n.getMessage

background.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 74 matching lines @@
   };
 
   modules.utils = {
     Utils: {
       getDocLink(link)
       {
         return "https://adblockplus.org/redirect?link=" + encodeURIComponent(link);
       },
       get appLocale()
       {
-        return parent.ext.i18n.locale.replace(/_/g, "-");
+        return chrome.i18n.getUILanguage();
       },
       get readingDirection()
       {
         return /^(?:ar|fa|he|ug|ur)\b/.test(this.appLocale) ? "rtl" : "ltr";
       }
     }
   };
 
   modules.prefs = {Prefs: new EventEmitter()};
   let prefs = {
@@ skipping 495 matching lines @@
       },
       filter: {
         text: "||example.com/some-annoying-popup$popup",
         whitelisted: false,
         userDefined: true,
         subscription: null
       }
     });
   });
 }());