Entry Points: Refactor Extensions Part 1. This moves the validation and entry point files to use a consistent syntax. This will facilitate auto-generation. Bug: angleproject:2263 Change-Id: Ica2dbffff3898103c6827ae7f6b1154a45d14a85 Reviewed-on: https://chromium-review.googlesource.com/841345 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>