Issue 4210 - Remove outdated workaround causing overeager element collapsing

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
@@ skipping 110 matching lines @@
   {
     if (/^(?!https?:)[\w-]+:/i.test(urls[i]))
       urls.splice(i--, 1);
   }
 
   return urls;
 }
 
 function checkCollapse(element)
 {
-  window.collapsing = true;
-
   var mediatype = typeMap[element.localName];
   if (!mediatype)
     return;
 
   var urls = getURLsFromElement(element);
   if (urls.length == 0)
     return;
 
   ext.backgroundPage.sendMessage(
     {
@@ skipping 449 matching lines @@
         var contentWindow = contentDocument.defaultView;
         if (contentDocument instanceof contentWindow.HTMLDocument)
         {
           // Prior to Chrome 37, content scripts cannot run in
           // dynamically created frames. Also on Chrome 37-40
           // document_start content scripts (like this one) don't
           // run either in those frames due to https://crbug.com/416907.
           // So we have to apply element hiding from the parent frame.
           if (!("init" in contentWindow))
             init(contentDocument);
-
-          // Moreover, "load" and "error" events aren't dispatched for elements
-          // in dynamically created frames due to https://crbug.com/442107.
-          // So we also have to apply element collpasing from the parent frame.
-          if (!contentWindow.collapsing)
-            Array.prototype.forEach.call(
-              contentDocument.querySelectorAll(Object.keys(typeMap).join(",")),
-              checkCollapse
-            );
         }
       }
     }
   }, true);
 
   return updateStylesheet;
 }
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
   window.updateStylesheet = init(document);
 }