D3D11: Consolidate constant buffer application. This will let the StateManager11 work more easily with dirty bits. BUG=angleproject:1390 BUG=angleproject:2052 Change-Id: I9738d02e69e2062feeba4237487ad8e9ae86e78b Reviewed-on: https://chromium-review.googlesource.com/659227 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>