This ensures we use the correct internal path in Chromium builds as
well.

Bug: angleproject:3162
Change-Id: I036dcbd8802f67162e5f5eccb6158910f0a5efcc
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2082134Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>