BUG=angleproject:1161

This is a continuation of the dirty bit refactor

Change-Id: If7d523e6200fef631051cab0bde47fdec8385c17
Reviewed-on: https://chromium-review.googlesource.com/312722Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Tested-by: Dian Xiang <dianx@google.com>