The multiprocess version of the DOMWINDOW/DOCSHELL leak detector relies on a process producing a "Completed ShutdownLeaks collections" message when it has finished collections, to know the point where the process should have cleaned up various windows and docshells, but right now there's no check that this message was actually produced. Bug 1135956 will have to be fixed before this, or the test harness will have to be aware of whether it is running in e10s mode or not, and made more lenient in the former case.