Some old webrtc threads no longer exist, while the "WebrtcCallThread" single-thread thread pool was added late in bug 1654112.

If you are touching the (long) list of threads of the media preset, you might be interested in knowning that the thread filter done by the profiler is a case insensitve substring search: https://searchfox.org/mozilla-central/rev/b80b92e2e10299ab405bdc4eb5109e9e23e25160/mozglue/baseprofiler/core/platform.cpp#656,677-678

So I think the current list of threads can be simplified a lot and made more future proof by including Audio,Media,Webrtc

Also, when I used the Media preset yesterday to file bug 1746156, I wondered why it didn't include the ipcmessages feature, as the Media pipeline involves activity on multiple processes (at least the content process + the RDD process, and sometimes the GMP process) and I think seeing the IPCs in profiles would be valuable.

Thanks, I think I have managed to capture this. The list is simpler though not remarkably shorter.

Backed out for causing failures at browser_interaction-between-interfaces.js.

Backout link: https://hg.mozilla.org/integration/autoland/rev/986ca78e8e52bd4620a3d2c794a60da16213bbde

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&selectedTaskRun=D-i3nB2FQ7utXqeZylOaJg.0&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=eccba94506f01f70acfba919fe6595392bbf753a

Failure log: https://treeherder.mozilla.org/logviewer?job_id=363081925&repo=autoland&lineNumber=4340

The ipcmessages feature was caught by a devtools test. I've updated that and it now passes locally.

https://hg.mozilla.org/mozilla-central/rev/0dd2a0923bc5
https://hg.mozilla.org/mozilla-central/rev/7bd87eee837f