Issue 4795 - Use modern JavaScript syntax

lib/stats.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 stats */
 
-let {Prefs} = require("prefs");
-let {BlockingFilter} = require("filterClasses");
-let {FilterNotifier} = require("filterNotifier");
+"use strict";
 
-let badgeColor = "#646464";
+const {Prefs} = require("prefs");
+const {BlockingFilter} = require("filterClasses");
+const {FilterNotifier} = require("filterNotifier");
+
+const badgeColor = "#646464";
 let blockedPerPage = new ext.PageMap();
 
 /**
  * Gets the number of requests blocked on the given page.
  *
  * @param  {Page} page
  * @return {Number}
  */
 exports.getBlockedPerPage = page => blockedPerPage.get(page) || 0;
 
@@ skipping 34 matching lines @@
             color: badgeColor,
             number: blocked
           };
         }
       }
 
       page.browserAction.setBadge(badge);
     }
   });
 });