These were causing unused variable warnings in Linux GCC builds.

BUG=angle:773

Change-Id: I860d425a1caef07a58f6ff1b6c113ad7b63283dc
Reviewed-on: https://chromium-review.googlesource.com/231856Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>