Issue 4243 - NS_ERROR_ILLEGAL_VALUE exception in utils.getFrames()

lib/child/elemHide.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 307 matching lines @@
     {
       this.sheet = null;
     });
   },
 
   observe: function(subject, topic, data)
   {
     if (topic != this.topic)
       return;
 
+    if (!subject.location || !subject.location.href)
+    {
+      // The window is in an invalid state - delay processing until it's ready.

[Thomas Greiner, 2016/07/14 14:19:21]

What are the reasons for the window being in an invalid state at this point?

Because if there can be windows that never reach a valid state then this fix
would cause an infinite loop in those cases.

[Wladimir Palant, 2016/07/14 15:19:42]

It seems that Nightly change the initialization sequence - so when
content-document-global-created notification fires the window sometimes isn't
fully initialized. After a runAsync call it always is however, I verified that.
No, a window being stuck in that state would be a huge Gecko bug. In fact, I
suspect that what we see now is already a Gecko bug - JavaScript isn't supposed
to see windows like that.

+      Utils.runAsync(() =>
+      {
+        if (!Cu.isDeadWrapper(subject))
+          this.observe(subject, topic, data)
+      });
+      return;
+    }
+
     port.emitWithResponse("elemhideEnabled", {
       frames: getFrames(subject),
       isPrivate: isPrivate(subject)
     }).then(({
       enabled, contentType, docDomain, thirdParty, location, filter,
       filterType
     }) =>
     {
       if (Cu.isDeadWrapper(subject))
       {
@@ skipping 27 matching lines @@
       else if (filter)
       {
         RequestNotifier.addNodeData(subject.document, subject.top, {
           contentType, docDomain, thirdParty, location, filter, filterType
         });
       }
     });
   }
 };
 observer.init();