web component test components/test/test-runs-query-builder.html times out in Chrome 85

[Hexcles]

Example: https://github.com/web-platform-tests/wpt.fyi/pull/2127/checks?check_run_id=1028311623#step:3:522

This passes on master with Chrome 84: https://github.com/web-platform-tests/wpt.fyi/runs/1023635956

[stephenmcgruer]

Also fails in 86 (https://github.com/web-platform-tests/wpt.fyi/issues/2128) and 87 (https://github.com/web-platform-tests/wpt.fyi/pull/2144).

Next step will be to bisect 84 --> 85, as long as it reproduces using Chromium builds as well (hopefully!).

[Hexcles]

So with the bisecting in #2136 , it comes down to https://chromium.googlesource.com/chromium/src/+log/32db5518e4b1bee1d11ee88e659139f6897843d2..319a121eef71f1659cb0cd5b99f80602b834a1f3

My bet is on https://chromium-review.googlesource.com/c/chromium/src/+/1530907

[stephenmcgruer]

Nice job! Have you been able to confirm a reproduction on 88, just to check?

I think we should pull in Leszek and a few others from their team, who might be able to help us identify how to debug this. We can build Chrome binaries locally and upload them to a GCP bucket to be used by the CI here (for debugging or trying fixes), but the first step is to get some experts involved I think :). Can you send them an email?

[Hexcles]

With help from Leszek, we added a temporary workaround to allow us to unpin Chrome version (#2266): https://github.com/web-platform-tests/wpt.fyi/blob/e2e2acca2b90c088d5d28ebf4afb2058370f987f/webapp/wct.conf.json#L12

but the root cause (which is suspected to be in the user land, and most likely web-component-tester) still remains unsolved.