When detected, add the necessary defines to actually use it.

Change-Id: I540c3e11e480be8aaab154ad91ee08cdc52319de
Reviewed-on: https://chromium-review.googlesource.com/988432
Commit-Queue: Frank Barchard <fbarchard@chromium.org>
Reviewed-by: Frank Barchard <fbarchard@chromium.org>