Roll Skia from 60a2ec03b662 to b87975c13381 (4 revisions)

https://skia.googlesource.com/skia.git/+log/60a2ec03b662..b87975c13381

2020-12-08 robertphillips@google.com Use the ManagedBackendTexture helper in fiddle_main
2020-12-08 johnstiles@google.com Add missing `degrees` function to SkSL intrinsics.
2020-12-08 csmartdalton@google.com Update viewer path renderer options for indirect tessellation
2020-12-08 bungeman@google.com System harfbuzz also means harfbuzz-icu.

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 jmbetancourt@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: jmbetancourt@google.com
Change-Id: If473e72ba969e4e938b66e04f59ce3a952836f44
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2579803
Reviewed-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@{#834808}