Roll Skia from efd828091d0c to d6af8bf96690 (3 revisions)

https://skia.googlesource.com/skia.git/+log/efd828091d0c..d6af8bf96690

2021-11-09 kjlubick@google.com [infra] Make jobs use Gold's public hashes
2021-11-09 johnstiles@google.com Add trace opcodes for function entry/exit.
2021-11-09 scroggo@google.com Remove unused variable 'heapIndex'

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://skia-autoroll.corp.goog/r/android-master-autoroll
Please CC scroggo@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/main/autoroll/README.md

Test: Presubmit checks will test this change.
Exempt-From-Owner-Approval: The autoroll bot does not require owner approval.
Bug: b/186777432
Change-Id: Ifa34edbe72eb99fd869954ef51434d3ea3d4c69b