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] Patch
Comment on attachment 337786 [details] Patch Attachment 337786 [details] did not pass win-ews (win): Output: http://webkit-queues.webkit.org/results/7293838 New failing tests: http/tests/security/contentSecurityPolicy/userAgentShadowDOM/allow-audio.html
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>
<rdar://problem/39406337>