Previously the Renderer11 would call directly into the state manager
sync methods. Instead make a single updateState method, and make
several state sync methods private to the manager. Also rename them
to clarify they're for syncing state, not for direct use.

BUG=angleproject:1156

Change-Id: I94880a744e7ade3895fa2a312a2436ba4ef38dba
Reviewed-on: https://chromium-review.googlesource.com/529705Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>