Issue 4795 - Use modern JavaScript syntax

lib/whitelisting.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
@@ skipping 42 matching lines @@
 let checkWhitelisted =
 /**
  * Gets the active whitelisting filter for the document associated
  * with the given page/frame, or null if it's not whitelisted.
  *
  * @param {Page}   page
  * @param {Frame}  [frame]
  * @param {number} [typeMask=RegExpFilter.typeMap.DOCUMENT]
  * @return {?WhitelistFilter}
  */
-exports.checkWhitelisted = function(page, frame, typeMask)
+exports.checkWhitelisted = (page, frame, typeMask) =>
 {
   if (typeof typeMask == "undefined")
     typeMask = RegExpFilter.typeMap.DOCUMENT;
 
   if (frame)
   {
     let filter = null;
 
     while (frame && !filter)
     {
@@ skipping 37 matching lines @@
 
 let getKey =
 /**
  * Gets the public key, previously recorded for the given page
  * and frame, to be considered for the $sitekey filter option.
  *
  * @param {Page}  page
  * @param {Frame} frame
  * @return {string}
  */
-exports.getKey = function(page, frame)
+exports.getKey = (page, frame) =>
 {
   let keys = sitekeys.get(page);
   if (!keys)
     return null;
 
   for (; frame != null; frame = frame.parent)
   {
     let key = keys[stringifyURL(frame.url)];
     if (key)
       return key;
@@ skipping 63 matching lines @@
 
 if (typeof chrome == "object")
   chrome.webRequest.onHeadersReceived.addListener(
     onHeadersReceived,
     {
       urls: ["http://*/*", "https://*/*"],
       types: ["main_frame", "sub_frame"]
     },
     ["responseHeaders"]
   );