Issue 309 - Don't use Shadow DOM in Chrome 32.0.1700

include.preload.js

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2014 Eyeo GmbH
  *
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  * it under the terms of the GNU General Public License version 3 as
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  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 var SELECTOR_GROUP_SIZE = 20;
 
 // Sets the currently used CSS rules for elemhide filters
 function setElemhideCSSRules(selectors)
 {
   if (selectors.length == 0)
     return;
 
   var style = document.createElement("style");
   style.setAttribute("type", "text/css");
 
-  // Use Shadow DOM if available to don't mess with web pages
-  // that rely on the order of their own <style> tags (#309)
-  if ("webkitCreateShadowRoot" in document.documentElement)
+  // Use Shadow DOM if available to don't mess with web pages that
+  // rely on the order of their own <style> tags. However the
+  // <shadow> element is broken in Chrome Chrome 32.0.1700 (#309)

[Thomas Greiner, 2014/04/17 12:24:17]

"in Chrome Chrome" ;)

[Sebastian Noack, 2014/04/17 12:30:32]

Done.

+  if ("webkitCreateShadowRoot" in document.documentElement && !/\bChrome\/32\.0\.1700\b/.test(navigator.userAgent))

[Felix Dahlke, 2014/04/17 12:05:38]

Is there no other way to figure out if the shadow element is being ignored?

[Sebastian Noack, 2014/04/17 12:24:17]

Please see the discussion at https://issues.adblockplus.org/ticket/309. Wladimir
suggested to check for presence of HTMLShadowElement. But that object exist and
even |document.createElement("shadow") instanceof HTMLShadowElement| returns
true. But it is completly ignored when the website is rendered.

[Thomas Greiner, 2014/04/17 12:24:17]

In what way is it broken? You mention that the "<shadow> element is ignored".
Would the following check help for this case?

typeof HTMLShadowElement != "undefined"

and/or

document.createElement("shadow") instanceof HTMLShadowElement

[Sebastian Noack, 2014/04/17 12:30:32]

Same effect as if it wouldn't be there. And since <shadow> is the insertion
point, that means that the page is always rendered empty.
No, see my previous comment.

   {
     var shadow = document.documentElement.webkitCreateShadowRoot();
     shadow.appendChild(document.createElement("shadow"));
     shadow.appendChild(style);
 
     try
     {
       document.querySelector("::content");
 
       for (var i = 0; i < selectors.length; i++)
@@ skipping 79 matching lines @@
     ext.backgroundPage.sendMessage({type: "add-key-exception", token: attr});
 
   ext.backgroundPage.sendMessage({type: "get-selectors"}, setElemhideCSSRules);
 }
 
 // In Chrome 18 the document might not be initialized yet
 if (document.documentElement)
   init();
 else
   window.setTimeout(init, 0);