Issue 4795 - Use modern JavaScript syntax

include.preload.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";
 
-let typeMap = {
+const typeMap = {
   "img": "IMAGE",
   "input": "IMAGE",
   "picture": "IMAGE",
   "audio": "MEDIA",
   "video": "MEDIA",
   "frame": "SUBDOCUMENT",
   "iframe": "SUBDOCUMENT",
   "object": "OBJECT",
   "embed": "OBJECT"
 };
@@ skipping 44 matching lines @@
   }
 
   return urls;
 }
 
 function getURLsFromMediaElement(element)
 {
   let urls = getURLsFromAttributes(element);
 
   for (let child of element.children)
+  {
     if (child.localName == "source" || child.localName == "track")
       urls.push.apply(urls, getURLsFromAttributes(child));
+  }
 
   if (element.poster)
     urls.push(element.poster);
 
   return urls;
 }
 
 function getURLsFromElement(element)
 {
   let urls;
@@ skipping 101 matching lines @@
 
   this.observer = new MutationObserver(this.observe.bind(this));
   this.trace = this.trace.bind(this);
 
   if (document.readyState == "loading")
     document.addEventListener("DOMContentLoaded", this.trace);
   else
     this.trace();
 }
 ElementHidingTracer.prototype = {
-  checkNodes: nodes =>
+  checkNodes(nodes)
   {
     let matchedSelectors = [];
 
     // Find all selectors that match any hidden element inside the given nodes.
     for (let selector of this.selectors)
     {
       for (let node of nodes)
       {
         let elements = node.querySelectorAll(selector);
         let matched = false;
@@ skipping 16 matching lines @@
       }
     }
 
     if (matchedSelectors.length > 0)
       ext.backgroundPage.sendMessage({
         type: "devtools.traceElemHide",
         selectors: matchedSelectors
       });
   },
 
-  onTimeout: function()
+  onTimeout()
   {
     this.checkNodes(this.changedNodes);
     this.changedNodes = [];
     this.timeout = null;
   },
 
-  observe: function(mutations)
+  observe(mutations)
   {
     // Forget previously changed nodes that are no longer in the DOM.
     for (let i = 0; i < this.changedNodes.length; i++)
     {
       if (!document.contains(this.changedNodes[i]))
         this.changedNodes.splice(i--, 1);
     }
 
     for (let mutation of mutations)
     {
@@ skipping 34 matching lines @@
         this.changedNodes.push(node);
     }
 
     // Check only nodes whose descendants have changed, and not more often
     // than once a second. Otherwise large pages with a lot of DOM mutations
     // (like YouTube) freeze when the devtools panel is active.
     if (this.timeout == null)
       this.timeout = setTimeout(this.onTimeout.bind(this), 1000);
   },
 
-  trace: function()
+  trace()
   {
     this.checkNodes([document]);
 
     this.observer.observe(
       document,
       {
         childList: true,
         attributes: true,
         subtree: true
       }
     );
   },
 
-  disconnect: function()
+  disconnect()
   {
     document.removeEventListener("DOMContentLoaded", this.trace);
     this.observer.disconnect();
     clearTimeout(this.timeout);
   }
 };
 
 function runInPageContext(fn, arg)
 {
   let script = document.createElement("script");
@@ skipping 100 matching lines @@
         type: "filters.get",
         what: "elemhideemulation"
       }, callback);
     },
     this.addSelectors.bind(this)
   );
 }
 ElemHide.prototype = {
   selectorGroupSize: 200,
 
-  createShadowTree: () =>
+  createShadowTree()
   {
     // Use Shadow DOM if available as to not mess with with web pages that
     // rely on the order of their own <style> tags (#309). However, creating
     // a shadow root breaks running CSS transitions. So we have to create
     // the shadow root before transistions might start (#452).
     if (!("createShadowRoot" in document.documentElement))
       return null;
 
     // Using shadow DOM causes issues on some Google websites,
     // including Google Docs, Gmail and Blogger (#1770, #2602, #2687).
@@ skipping 12 matching lines @@
     {
       runInPageContext(() =>
       {
         let ourShadowRoot = document.documentElement.shadowRoot;
         if (!ourShadowRoot)
           return;
         let desc = Object.getOwnPropertyDescriptor(Element.prototype, "shadowRoot");
         let shadowRoot = Function.prototype.call.bind(desc.get);
 
         Object.defineProperty(Element.prototype, "shadowRoot", {
-          configurable: true, enumerable: true, get: function()
+          configurable: true, enumerable: true, get()
           {
             let shadow = shadowRoot(this);
             return shadow == ourShadowRoot ? null : shadow;
           }
         });
       }, null);
     }
 
     return shadow;
   },
 
-  addSelectors: function(selectors)
+  addSelectors(selectors)
   {
     if (selectors.length == 0)
       return;
 
     if (!this.style)
     {
       // Create <style> element lazily, only if we add styles. Add it to
       // the shadow DOM if possible. Otherwise fallback to the <head> or
       // <html> element. If we have injected a style element before that
       // has been removed (the sheet property is null), create a new one.
@@ skipping 30 matching lines @@
     //  is! Edge apparently has no such limit.)
     // [1] - https://github.com/WebKit/webkit/blob/1cb2227f6b2a1035f7bdc46e5ab69debb75fc1de/Source/WebCore/css/RuleSet.h#L68
     for (let i = 0; i < selectors.length; i += this.selectorGroupSize)
     {
       let selector = selectors.slice(i, i + this.selectorGroupSize).join(", ");
       this.style.sheet.insertRule(selector + "{display: none !important;}",
                                   this.style.sheet.cssRules.length);
     }
   },
 
-  apply: function()
+  apply()
   {
     let selectors = null;
     let elemHideEmulationLoaded = false;
 
     let checkLoaded = function()
     {
       if (!selectors || !elemHideEmulationLoaded)
         return;
 
       if (this.tracer)
@@ skipping 23 matching lines @@
       checkLoaded();
     });
   }
 };
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
   wrapWebSocket();
 
-  let elemhide = new ElemHide();
+  // This variable is also used by our other content scripts, outside of the
+  // current scope.
+  var elemhide = new ElemHide();
   elemhide.apply();
 
   document.addEventListener("error", event =>
   {
     checkCollapse(event.target);
   }, true);
 
   document.addEventListener("load", event =>
   {
     let element = event.target;
     if (/^i?frame$/.test(element.localName))
       checkCollapse(element);
   }, true);
 }