The warning does not seem to occur on the Chromium bots, but shows
when compiling ANGLE standalone.

BUG=595836

Change-Id: I3c22bbea263223f9e92f82229817e9e9894a46ad
Reviewed-on: https://chromium-review.googlesource.com/335576Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>