Issue 4795 - Use modern JavaScript syntax

lib/requestBlocker.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/>.
  */
 
 /** @module requestBlocker */
 
 "use strict";
 
-let {Filter, RegExpFilter, BlockingFilter} = require("filterClasses");
-let {Subscription} = require("subscriptionClasses");
-let {defaultMatcher} = require("matcher");
-let {FilterNotifier} = require("filterNotifier");
-let {Prefs} = require("prefs");
-let {checkWhitelisted, getKey} = require("whitelisting");
-let {stringifyURL, extractHostFromFrame, isThirdParty} = require("url");
-let {port} = require("messaging");
-let devtools = require("devtools");
+const {Filter, RegExpFilter, BlockingFilter} = require("filterClasses");
+const {Subscription} = require("subscriptionClasses");
+const {defaultMatcher} = require("matcher");
+const {FilterNotifier} = require("filterNotifier");
+const {Prefs} = require("prefs");
+const {checkWhitelisted, getKey} = require("whitelisting");
+const {stringifyURL, extractHostFromFrame, isThirdParty} = require("url");
+const {port} = require("messaging");
+const devtools = require("devtools");
 
 // Chrome can't distinguish between OBJECT_SUBREQUEST and OBJECT requests.
 RegExpFilter.typeMap.OBJECT_SUBREQUEST = RegExpFilter.typeMap.OBJECT;
 
 function onBeforeRequestAsync(page, url, type, docDomain,
                               thirdParty, sitekey,
                               specificOnly, filter)
 {
   if (filter)
     FilterNotifier.emit("filter.hitCount", filter, 0, 0, page);
@@ skipping 113 matching lines @@
 
 port.on("request.websocket", (msg, sender) =>
 {
   return ext.webRequest.onBeforeRequest._dispatch(
     new URL(msg.url),
     "WEBSOCKET",
     sender.page,
     sender.frame
   ).indexOf(false) != -1;
 });