Roll Skia from 77ba8103d34f to af9b58e287b5 (6 revisions)

https://skia.googlesource.com/skia.git/+log/77ba8103d34f..af9b58e287b5

2021-01-14 johnstiles@google.com Fix fragment processors and unit tests which mix ints and floats.
2021-01-14 johnstiles@google.com Factor out SPIR-V typecasting helper functions.
2021-01-13 johnstiles@google.com Revert "[svg] Perform colorspace conversions for filter effects"
2021-01-13 brianosman@google.com Support ES2-compliant for loops in SkSL-to-SkVM
2021-01-13 tdenniston@google.com [svg] Perform colorspace conversions for filter effects
2021-01-13 bsalomon@google.com Reland "Push SkYUVAInfo into GrYUVToRGBEffect."

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-autoroll
Please CC ethannicholas@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/master/autoroll/README.md

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux-blink-rel;luci.chromium.try:linux-chromeos-compile-dbg;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Cq-Do-Not-Cancel-Tryjobs: true
Bug: None
Tbr: ethannicholas@google.com
Change-Id: I488f83696ce1b1dffee6083b051e0593aee2e2bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628547Reviewed-by: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Commit-Queue: chromium-autoroll <chromium-autoroll@skia-public.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#843354}

DEPS

@@ -199,7 +199,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling Skia
   # and whatever else without interference from each other.
-  'skia_revision': '77ba8103d34fc821bdbba9f2a54a7d7371d1d56f',
+  'skia_revision': 'af9b58e287b53a406d59e999883d0744bf5c966c',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.