Example flaky run:
https://ci.chromium.org/p/chromium/builders/luci.chromium.ci/Win10%20Tests%20x64%20%28dbg%29/4013

Flakiness dashboard which shows ~15 tests flaking after 45 seconds:
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=extensions_browsertests&tests=PrinterProviderApiTest.PrintJobSuccess&sortOrder=forward

Stack trace from a flaky run:
[ RUN      ] PrinterProviderApiTest.PrintJobFailed

DevTools listening on ws://127.0.0.1:49928/devtools/browser/501d7a7e-d9f8-4e30-b753-deb55aa69d74
[512:3448:1030/124406.478:275390:ERROR:direct_composition_surface_win.cc(165)] EGL_ANGLE_flexible_surface_compatibility not supported