It's better to maintain the code outside of a generator script. It
gives easier formatting and updating.

BUG=angleproject:1455

Change-Id: I2b4383f1ed01545004de10024d03879201e2bf41
Reviewed-on: https://chromium-review.googlesource.com/365410Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>