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 316 matching lines @@
   },
 
   disconnect: function()
   {
     this.document.removeEventListener("DOMContentLoaded", this.trace);
     this.observer.disconnect();
     clearTimeout(this.timeout);
   }
 };
 
-function reinjectStyleSheetWhenRemoved(document, style)
-{
-  if (!MutationObserver)
-    return null;
-
-  var parentNode = style.parentNode;
-  var observer = new MutationObserver(function()
-  {
-    if (style.parentNode != parentNode)
-      parentNode.appendChild(style);
-  });
-
-  observer.observe(parentNode, {childList: true});
-  return observer;
-}
-
 function runInPage(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);
 }
 
+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++)
+          style.sheet.addRule(rules[i].selectorText, "display: none !important;");
+
+        style.id = id;
+        runInPage(
+          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 protectStyleSheet(document, style)
 {
   style.id = id;
 
   runInPage(function(id)
   {
     var style = document.getElementById(id) ||
                 document.documentElement.shadowRoot.getElementById(id);
     style.removeAttribute("id");
 
@@ skipping 266 matching lines @@
   }, true);
 
   return updateStylesheet;
 }
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
   window.updateStylesheet = init(document);
 }