It's not a bug in WebKit, but in the GLib implementation of TestWebKitAPI::Util::run(). We try to quit the main loop that hasn't been initialized. We should always use RunLoop::current() instead.
hmm, fixing Uril::run() works for ReleaseInNonMainThread, but not for ReleaseInNonMainThreadDestroyInMainThread, because it ends up using scheduleOnMainThread and the generic implementation of that used RunLoop::main() too, so we need to initialize the main loop in that test.
Created attachment 337786 [details]
Comment on attachment 337786 [details]
Attachment 337786 [details] did not pass win-ews (win):
New failing tests:
Created attachment 337795 [details]
Archive of layout-test-results from ews200 for win-future
The attached test failures were seen while running run-webkit-tests on the win-ews.
Bot: ews200 Port: win-future Platform: CYGWIN_NT-6.1-2.9.0-0.318-5-3-x86_64-64bit
Committed r230624: <https://trac.webkit.org/changeset/230624>