1594018 - Intermittent "unable to find test window" when running web-platform tests with mDNS hostname obfuscation enabled

Status: NEW

(Core :: WebRTC: Networking, enhancement, P3)

Description

[Dan Minor [:dminor]]

I've hit an intermittent "unable to find test window" when running data channel web-platform tests with mDNS hostname obfuscation enabled on windows 7.

If I increase the timeout in the harness here [1] the failure seems to go away. I think the problem is with unregistering mDNS hostnames. If I skip unregistering at shutdown in PeerConnectionMedia, the intermittent also seems to go away. Currently, each mDNS hostname is unregistered with the mdns service individually, which results in one IPC message per hostname. The RTCDataChannel-send.html test accumulates 20 peer connections by the time it shuts down, and it seems to be the trigger for the intermittent.

It would be nice to batch these up, however in most cases each PeerConnectionMedia instance is only holding on to a single hostname, so the approach of sending an array of hostnames to unregister would require coordinating between PeerConnectionMedia instances.

[1] https://searchfox.org/mozilla-central/rev/3300072e993ae05d50d5c63d815260367eaf9179/testing/web-platform/tests/tools/wptrunner/wptrunner/executors/executormarionette.py#190