Remove references to software rendering in Renderer9. BUG=angle:641 Change-Id: I3724c2504d43eae0528e8c72eb51e96c9d7c7a71 Reviewed-on: https://chromium-review.googlesource.com/198377 Reviewed-by: Nicolas Capens <nicolascapens@chromium.org> Reviewed-by: Shannon Woods <shannonwoods@chromium.org> Tested-by: Geoff Lang <geofflang@chromium.org>