This was giving a compile error on OSX. Also update the logic
slightly.

BUG=angleproject:963

Change-Id: I1ac64aa0908a58d9780054084d5c205c61848763
Reviewed-on: https://chromium-review.googlesource.com/263730Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>