When using the zero color mask workaround in StateManager9, the blend state and
blend equation were being modified.  This caused inconsistant state if the
workaround stopped being used in subsequent draw calls.  To deal with this
issue, dirty the BLEND_ENABLED and BLEND_EQUATION states when the COLOR_MASK
changes and dirty the COLOR_MASK state wheneither BLEND_ENABLED or
BLEND_EQUATION changes.

BUG=597107

Change-Id: I03de934b419b7593e4863838720ced1e5773c092
Reviewed-on: https://chromium-review.googlesource.com/339280Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Tryjob-Request: Geoff Lang <geofflang@chromium.org>