Fix Chromium build of angle_end2end_tests BUG=angleproject:892 Change-Id: I9922046fc9e4d82d7034405f5952263f982c6529 Reviewed-on: https://chromium-review.googlesource.com/278159 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Kenneth Russell <kbr@chromium.org> Tested-by: Corentin Wallez <cwallez@chromium.org>