Issue 3824 - Move "use strict" into IIFE for compatibility with Kitt

lib/polyfills/fetch.js

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-"use strict";
-
 (function(global)
 {
+  "use strict";
+
   function Response(xhr)
   {
     this._xhr = xhr;
   }
   Response.prototype = {
     get ok()
     {
       return this._xhr.status >= 200 && this._xhr.status <= 299;
     },
     text: function()
@@ skipping 34 matching lines @@
       return builtinFetch(url, init).catch(function(reason)
       {
         if (new URL(url, document.URL).protocol == "chrome-extension:")
           return fetch(url);
         throw reason;
       });
     };
   else
     global.fetch = fetch;
 })(this);