This eliminates some of the redundant work we do in uniform state
updates. Driver uniforms and constant buffers are no longer synched
with every draw call, but only when the StateManager11 thinks they
might be dirty. Should improve overall draw call throughput.

BUG=angleproject:1155
BUG=angleproject:1390

Change-Id: I351c23fb18dcb3ef2f79e3b4f411e1e09c6300dc
Reviewed-on: https://chromium-review.googlesource.com/659228
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>