Fix warning about unexpected mock function call. BUG=angleproject:985 Change-Id: If2138d8ec9a4f99adaf4ef1a4cbeeab6b0bf9f2c Reviewed-on: https://chromium-review.googlesource.com/267349 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>