Remove an unused mRenderer member from Program and initialize TF members. BUG=angle:731 Change-Id: Ie11c80ce1f3a8c3d08145dfb4a075ac0e022ae38 Reviewed-on: https://chromium-review.googlesource.com/239218 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>