The data holds the GL state, caps, extensions, texture caps, and
current client version.

BUG=angle:789

Change-Id: Icd15d806e14490f39041dea663ab2461a6a76090
Reviewed-on: https://chromium-review.googlesource.com/226060Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>