Issue 4364 - Drop support for Chrome 29-40 and remove legacy code

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/>.
  */
 
 var MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
-var SELECTOR_GROUP_SIZE = 200;
 
 var typeMap = {
   "img": "IMAGE",
   "input": "IMAGE",
   "picture": "IMAGE",
   "audio": "MEDIA",
   "video": "MEDIA",
   "frame": "SUBDOCUMENT",
   "iframe": "SUBDOCUMENT",
   "object": "OBJECT",
@@ skipping 299 matching lines @@
   },
 
   disconnect: function()
   {
     document.removeEventListener("DOMContentLoaded", this.trace);
     this.observer.disconnect();
     clearTimeout(this.timeout);
   }
 };
 
-function runInDocument(fn, arg)
+function runInPageContext(fn, arg)
 {
   var script = document.createElement("script");
   script.type = "application/javascript";
   script.async = false;
   script.textContent = "(" + fn + ")(" + JSON.stringify(arg) + ");";
   document.documentElement.appendChild(script);
   document.documentElement.removeChild(script);
 }
 
 // Neither Chrome[1] nor Safari allow us to intercept WebSockets, and therefore
@@ skipping 14 matching lines @@
       type: "request.websocket",
       url: event.detail.url
     }, function (block)
     {
       document.dispatchEvent(
         new CustomEvent(eventName + "-" + event.detail.url, {detail: block})
       );
     });
   });
 
-  runInDocument(function(eventName)
+  runInPageContext(function(eventName)
   {
     // As far as possible we must track everything we use that could be
     // sabotaged by the website later in order to circumvent us.
     var RealWebSocket = WebSocket;
     var closeWebSocket = Function.prototype.call.bind(RealWebSocket.prototype.close);
     var addEventListener = document.addEventListener.bind(document);
     var removeEventListener = document.removeEventListener.bind(document);
     var dispatchEvent = document.dispatchEvent.bind(document);
     var CustomEvent = window.CustomEvent;
 
@@ skipping 39 matching lines @@
       OPEN: {value: RealWebSocket.OPEN, enumerable: true},
       CLOSING: {value: RealWebSocket.CLOSING, enumerable: true},
       CLOSED: {value: RealWebSocket.CLOSED, enumerable: true},
       prototype: {value: RealWebSocket.prototype}
     });
 
     RealWebSocket.prototype.constructor = WebSocket;
   }, eventName);
 }
 
-function init()
-{
-  var shadow = null;
-  var style = null;
-  var observer = null;
-  var tracer = null;
-
-  wrapWebSocket();
-
-  function getPropertyFilters(callback)
-  {
-    ext.backgroundPage.sendMessage({
-      type: "filters.get",
-      what: "cssproperties"
-    }, callback);
-  }
-  var propertyFilters = new CSSPropertyFilters(window, getPropertyFilters,
-                                               addElemHideSelectors);
-
-  // Use Shadow DOM if available to don't mess 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).
-  //
-  // Also, using shadow DOM causes issues on some Google websites,
-  // including Google Docs, Gmail and Blogger (#1770, #2602, #2687).
-  if ("createShadowRoot" in document.documentElement &&
-      !/\.(?:google|blogger)\.com$/.test(document.domain))
-  {
-    shadow = document.documentElement.createShadowRoot();
+function ElemHide()
+{
+  this.shadow = this.createShadowTree();
+  this.style = null;
+  this.tracer = null;
+
+  this.propertyFilters = new CSSPropertyFilters(
+    window,
+    function(callback)
+    {
+      ext.backgroundPage.sendMessage({
+        type: "filters.get",
+        what: "cssproperties"
+      }, callback);
+    },
+    this.addSelectors.bind(this)
+  );
+}
+ElemHide.prototype = {
+  selectorGroupSize: 200,
+
+  createShadowTree: function()
+  {
+    // Use Shadow DOM if available as to not mess with with web pages that
+    // rely on the order of their own <style> tags (#309). However, creating
+    // a shadow root breaks running CSS transitions. So we have to create
+    // the shadow root before transistions might start (#452).
+    if (!("createShadowRoot" in document.documentElement))
+      return null;
+
+    // Using shadow DOM causes issues on some Google websites,
+    // including Google Docs, Gmail and Blogger (#1770, #2602, #2687).
+    if (/\.(?:google|blogger)\.com$/.test(document.domain))
+      return null;
+
+    var shadow = document.documentElement.createShadowRoot();
     shadow.appendChild(document.createElement("shadow"));
 
-    // Stop the website from messing with our shadowRoot
+    // Stop the website from messing with our shadow root (#4191, #4298).
     if ("shadowRoot" in Element.prototype)
     {
-      runInDocument(function()
+      runInPageContext(function()
       {
         var ourShadowRoot = document.documentElement.shadowRoot;
         var desc = Object.getOwnPropertyDescriptor(Element.prototype, "shadowRoot");
         var shadowRoot = Function.prototype.call.bind(desc.get);
 
         Object.defineProperty(Element.prototype, "shadowRoot", {
           configurable: true, enumerable: true, get: function()
           {
             var shadow = shadowRoot(this);
             return shadow == ourShadowRoot ? null : shadow;
           }
         });
       }, null);
     }
-  }
-
-  function addElemHideSelectors(selectors)
+
+    return shadow;
+  },
+
+  addSelectors: function(selectors)
   {
     if (selectors.length == 0)
       return;
 
-    if (!style)
+    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.
-      style = document.createElement("style");
-      (shadow || document.head || document.documentElement).appendChild(style);
+      this.style = document.createElement("style");
+      (this.shadow || document.head
+                   || document.documentElement).appendChild(this.style);
 
       // It can happen that the frame already navigated to a different
       // document while we were waiting for the background page to respond.
       // In that case the sheet property will stay null, after addind the
       // <style> element to the shadow DOM.
-      if (!style.sheet)
+      if (!this.style.sheet)
         return;
     }
 
     // If using shadow DOM, we have to add the ::content pseudo-element
     // before each selector, in order to match elements within the
     // insertion point.
-    if (shadow)
+    if (this.shadow)
     {
       var preparedSelectors = [];
       for (var i = 0; i < selectors.length; i++)
       {
         var subSelectors = splitSelector(selectors[i]);
         for (var j = 0; j < subSelectors.length; j++)
           preparedSelectors.push("::content " + subSelectors[j]);
       }
       selectors = preparedSelectors;
     }
 
     // Safari only allows 8192 primitive selectors to be injected at once[1], we
     // therefore chunk the inserted selectors into groups of 200 to be safe.
     // (Chrome also has a limit, larger... but we're not certain exactly what it
     //  is! Edge apparently has no such limit.)
     // [1] - https://github.com/WebKit/webkit/blob/1cb2227f6b2a1035f7bdc46e5ab69debb75fc1de/Source/WebCore/css/RuleSet.h#L68
-    for (var i = 0; i < selectors.length; i += SELECTOR_GROUP_SIZE)
-    {
-      var selector = selectors.slice(i, i + SELECTOR_GROUP_SIZE).join(", ");
-      style.sheet.addRule(selector, "display: none !important;");
-    }
-  };
-
-  var updateStylesheet = function()
+    for (var i = 0; i < selectors.length; i += this.selectorGroupSize)
+    {
+      var selector = selectors.slice(i, i + this.selectorGroupSize).join(", ");
+      this.style.sheet.addRule(selector, "display: none !important;");
+    }
+  },
+
+  apply: function()
   {
     var selectors = null;
-    var CSSPropertyFiltersLoaded = false;
+    var propertyFiltersLoaded = false;
 
     var checkLoaded = function()
     {
-      if (!selectors || !CSSPropertyFiltersLoaded)
+      if (!selectors || !propertyFiltersLoaded)
         return;
 
-      if (observer)
-        observer.disconnect();
-      observer = null;
-
-      if (tracer)
-        tracer.disconnect();
-      tracer = null;
-
-      if (style && style.parentElement)
-        style.parentElement.removeChild(style);
-      style = null;
-
-      addElemHideSelectors(selectors.selectors);
-      propertyFilters.apply();
+      if (this.tracer)
+        this.tracer.disconnect();
+      this.tracer = null;
+
+      if (this.style && this.style.parentElement)
+        this.style.parentElement.removeChild(this.style);
+      this.style = null;
+
+      this.addSelectors(selectors.selectors);
+      this.propertyFilters.apply();
 
       if (selectors.trace)
-        tracer = new ElementHidingTracer(selectors.selectors);
-    };
+        this.tracer = new ElementHidingTracer(selectors.selectors);
+    }.bind(this);
 
     ext.backgroundPage.sendMessage({type: "get-selectors"}, function(response)
     {
       selectors = response;
       checkLoaded();
     });
 
-    propertyFilters.load(function()
-    {
-      CSSPropertyFiltersLoaded = true;
+    this.propertyFilters.load(function()
+    {
+      propertyFiltersLoaded = true;
       checkLoaded();
     });
-  };
-
-  updateStylesheet();
+  }
+};
+
+if (document instanceof HTMLDocument)
+{
+  checkSitekey();
+  wrapWebSocket();
+
+  var elemhide = new ElemHide();
+  elemhide.apply();
 
   document.addEventListener("error", function(event)
   {
     checkCollapse(event.target);
   }, true);
 
   document.addEventListener("load", function(event)
   {
     var element = event.target;
     if (/^i?frame$/.test(element.localName))
       checkCollapse(element);
   }, true);
-
-  return updateStylesheet;
-}
-
-if (document instanceof HTMLDocument)
-{
-  checkSitekey();
-  window.updateStylesheet = init();
-}
+}