Reland "SkMixerColorFilter GPU impl"

This reverts commit c2949ec67b92e455edd58e470564023c37df6e7a.

Reason for revert: not related to crossfade

Original change's description:
> Revert "SkMixerColorFilter GPU impl"
> 
> This reverts commit e80f7eb9d6a15d42827108700990291d3efb5995.
> 
> Reason for revert: break crossfade in chrome roll?
> 
> Original change's description:
> > SkMixerColorFilter GPU impl
> > 
> > Bug: skia:
> > Change-Id: Ia1e25e0c99737d9720c17f92f0d76a1cb7897ea8
> > Reviewed-on: https://skia-review.googlesource.com/c/skia/+/193163
> > Commit-Queue: Florin Malita <fmalita@chromium.org>
> > Reviewed-by: Brian Salomon <bsalomon@google.com>
> 
> TBR=bsalomon@google.com,ethannicholas@google.com,fmalita@chromium.org,reed@google.com
> 
> Change-Id: Ib9464fcabc649b95ba131146690d6208af728436
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: skia:
> Reviewed-on: https://skia-review.googlesource.com/c/skia/+/197760
> Reviewed-by: Mike Reed <reed@google.com>
> Commit-Queue: Mike Reed <reed@google.com>

TBR=bsalomon@google.com,ethannicholas@google.com,fmalita@chromium.org,reed@google.com

Change-Id: Ie96e80e153aeab16c4ea35d5f1350372060228aa
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/197763
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>
7 files changed