Improves the readability of the implementations and more closely mirrors
the GL commands.

Change-Id: Ifa7bc55751d50271eb01fd87e4efdc69f00c2c48
Reviewed-on: https://chromium-review.googlesource.com/239845Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Tested-by: Geoff Lang <geofflang@chromium.org>