This will allow us to eventually make a presubmit script for ANGLE,
and also will help new contributors who aren't as familiar with
the style guide.

One outstanding issue is the lack of proper breaking before array
initializers. We don't use arrays all over the place, but this
will likely require a patch for clang.

BUG=angleproject:762

Change-Id: I4702b1fcdfa10b7682b07316be59ec67bcf84943
Reviewed-on: https://chromium-review.googlesource.com/285901Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>