Issue 4191 - Restore rules for reinjected stylesheets

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 321 matching lines @@
     this.observer.disconnect();
     clearTimeout(this.timeout);
   }
 };
 
 function reinjectStyleSheetWhenRemoved(document, style)
 {
   if (!MutationObserver)
     return null;
 
+  var rules = style.sheet.rules;
   var parentNode = style.parentNode;
   var observer = new MutationObserver(function()
   {
     if (style.parentNode != parentNode)
+    {
       parentNode.appendChild(style);
+
+      if (style.sheet.rules.length == 0)
+      {
+        for (var i = 0; i < rules.length; i += 1)
+          style.sheet.addRule(rules[i].selectorText, "display: none !important;");
+
+        style.id = id;
+        injectJS(
+          function(id)
+          {
+            var style = document.getElementById(id) ||
+                        document.documentElement.shadowRoot.getElementById(id);
+            style.removeAttribute("id");
+            Object.defineProperty(style.sheet, "disabled",
+                                  {value: false, enumerable: true});
+          }, id
+        );
+      }
+    }
   });
 
   observer.observe(parentNode, {childList: true});
   return observer;
 }
 
 function injectJS(f)
 {
   var args = JSON.stringify(Array.prototype.slice.call(arguments, 1));
   args = args.substring(1, args.length - 1);
@@ skipping 307 matching lines @@
   }, true);
 
   return updateStylesheet;
 }
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
   window.updateStylesheet = init(document);
 }