Issue 4243 - NS_ERROR_ILLEGAL_VALUE exception in utils.getFrames()

lib/child/elemHide.js

Index: lib/child/elemHide.js
===================================================================
--- a/lib/child/elemHide.js
+++ b/lib/child/elemHide.js
@@ -320,16 +320,27 @@ let observer = {
     });
   },
 
   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
     }) =>
     {