Guard lowp changes

Chromium uses the lowp code, we have to stage the changes.

TBR=
Change-Id: I45e97a51eca285c9afc71926bbf736a03d0d146c
Reviewed-on: https://skia-review.googlesource.com/33765
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
1 file changed