Issue 4191 - Check shadowRoot getter exists before wrapping

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 439 matching lines @@
   //
   // 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();
     shadow.appendChild(document.createElement("shadow"));
 
     // Stop the website from messing with our shadowRoot
-    runInDocument(document, function()
+    if ("shadowRoot" in Element.prototype)
     {
-      var ourShadowRoot = document.documentElement.shadowRoot;
-      var desc = Object.getOwnPropertyDescriptor(Element.prototype, "shadowRoot");
-      var shadowRoot = Function.prototype.call.bind(desc.get);
+      runInDocument(document, 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", {
-        conifgurable: true, enumerable: true, get: function()
-        {
-          var shadow = shadowRoot(this);
-          return shadow == ourShadowRoot ? null : shadow;
-        }
-      });
-    }, null);
+        Object.defineProperty(Element.prototype, "shadowRoot", {
+          conifgurable: true, enumerable: true, get: function()
+          {
+            var shadow = shadowRoot(this);
+            return shadow == ourShadowRoot ? null : shadow;
+          }
+        });
+      }, null);
+    }
   }
 
   function addElemHideSelectors(selectors)
   {
     if (selectors.length == 0)
       return;
 
     if (!style)
     {
       // Create <style> element lazily, only if we add styles. Add it to
@@ skipping 124 matching lines @@
   }, true);
 
   return updateStylesheet;
 }
 
 if (document instanceof HTMLDocument)
 {
   checkSitekey();
   window.updateStylesheet = init(document);
 }