Roll Skia from 5a2a7b3096d0 to 4926b07217f0 (7 revisions)

https://skia.googlesource.com/skia.git/+log/5a2a7b3096d0..4926b07217f0

2020-06-04 michaelludwig@google.com Revert "Improve scissor state tracking in GrRTC"
2020-06-04 michaelludwig@google.com Improve scissor state tracking in GrRTC
2020-06-04 mtklein@google.com refine __chkstk_darwin() workaround
2020-06-04 mtklein@google.com remove templates from SkSwizzler_opts
2020-06-04 herb@google.com Make vertex structs private
2020-06-04 herb@google.com Remove unused vertex filler
2020-06-04 johnstiles@google.com Update GrFragmentProcessor::SwizzleOutput to use a child FP.

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 tdenniston@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
Bug: None
Tbr: tdenniston@google.com
Change-Id: I74a1eda69a59a9aee58d9d2cb86cb34c3ff7c3da
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2231598Reviewed-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@{#775281}

DEPS

@@ -182,7 +182,7 @@ 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': '5a2a7b3096d05f7993fc2d4a48432628d6779f4b',
+  'skia_revision': '4926b07217f07e8f5ff1dba15d23bab960ffded3',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.