This will make it easier to roll ANGLE in WebKit.

Bug: angleproject:3439
Change-Id: Icd4a5a2d5dcabb6cf13d4b46a7547f49610fa4b3
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1743057
Commit-Queue: James Darpinian <jdarpinian@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>