In "webkit_layout_tests on Windows-10-10586".

https://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win10/builds/25244

This is a new failure. Can be just a hiccup.
https://test-results.appspot.com/dashboards/flakiness_dashboard.html#testType=webkit_layout_tests&tests=http%2Ftests%2Fwebfont%2Fslow-loading.html
Note that the flakiness dashboard lacks data for recent runs.