BUG=angleproject:1161

Dirty bit notifications are used in GL for state tracking, but not D3D.
Before, D3D would use memcmp to check a change in state for every call.
This showed up as a hot spot in the perf test runs. Hence, switching D3D
over to the dirty bit system similar to GL backend will help.

Change-Id: I482edc852f1dcc888af3038ff3a61916496a02bc
Reviewed-on: https://chromium-review.googlesource.com/305295Reviewed-by: Geoff Lang <geofflang@chromium.org>
Tryjob-Request: Dian Xiang <dianx@google.com>
Tested-by: Jamie Madill <jmadill@chromium.org>