This makes it in a centralized location where it can work with dirty
bits.

BUG=angleproject:1387

Change-Id: I3bfeb53c265d1679f6b8556941c1d9d77747aa24
Reviewed-on: https://chromium-review.googlesource.com/648486
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>