Add extensions to disable client arrays. Chrome doesn't allow any client data in its command buffer. Add an ANGLE extension to request a context that disallows client data. BUG=602737 Change-Id: If9d5144daea3c629a73562396000df59a671aad3 Reviewed-on: https://chromium-review.googlesource.com/441986 Commit-Queue: Geoff Lang <geofflang@chromium.org> Reviewed-by: Jamie Madill <jmadill@chromium.org>