Roll Skia from 77960d9addc8 to a9be76de8b43 (6 revisions)

https://skia.googlesource.com/skia.git/+log/77960d9addc8..a9be76de8b43

2020-09-22 johnstiles@google.com Reduce the number of inliner temporaries by swizzling.
2020-09-22 johnstiles@google.com Calculate texture clamping X/Y coordinates in parallel.
2020-09-22 fmalita@chromium.org Fix skia_use_ffmpeg builds
2020-09-22 brianosman@google.com Change default of fBuiltinFMASupport back to false
2020-09-22 michaelludwig@google.com Use analytic coverage FPs with MSAA
2020-09-22 brianosman@google.com Remove RTAdjust plumbing

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 csmartdalton@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: csmartdalton@google.com
Change-Id: I67e2fe58ef1d8f1c463aa289b3177bd8b4c6630d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2424410Reviewed-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@{#809403}

DEPS

@@ -195,7 +195,7 @@ 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': '77960d9addc8b89ca0fff5b84bfed0f0e4970858',
+  'skia_revision': 'a9be76de8b43fc2e0ca705f93235a96b96394a7d',
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling V8
   # and whatever else without interference from each other.