Looks like they're timing out or are not finishing.
Sample failures:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Win10%20Tests%20x64/26094
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Win10%20Tests%20x64/26100
Log:
[ RUN ] WebRtcCaptureFromElementBrowserTest.VerifyCanvasCaptureOffscreenCanvasFrames
DevTools listening on ws://127.0.0.1:58511/devtools/browser/b4f78c77-c6a1-483f-b610-b4571ac94d58
[ RUN ] WebRtcCaptureFromElementBrowserTest.VerifyCanvasCaptureOffscreenCanvasFrames
DevTools listening on ws://127.0.0.1:60126/devtools/browser/38832f41-138c-47fd-8204-b36580207a93
[ RUN ] WebRtcCaptureFromElementBrowserTest.VerifyCanvasCaptureOffscreenCanvasFrames
DevTools listening on ws://127.0.0.1:60133/devtools/browser/a6d9c299-9f30-453c-98fa-72a62fcd0cf8
[ RUN ] WebRtcCaptureFromElementBrowserTest.VerifyCanvasCaptureOffscreenCanvasFrames
DevTools listening on ws://127.0.0.1:60142/devtools/browser/0effb8f3-6b52-43fb-ae26-14dea09b8418
Comment 1 by bugdroid1@chromium.org
, Aug 1