I observed this on Chromium-Linux EWS, commit-queue, and Chromium-Linux bot in build.webkit.org. e.g. http://build.webkit.org/builders/Chromium%20Linux%20Release%20%28Tests%29/builds/42199/steps/layout-test/logs/stdio
Fixed by https://src.chromium.org/viewvc/chrome?view=rev&revision=177952 http://trac.webkit.org/changeset/140368
Tests were fixed by Nico in http://src.chromium.org/viewvc/chrome?view=rev&revision=177952 .