Roll Skia from af2f73c1bbd3 to ef6bc4d7c581 (2 revisions)

https://skia.googlesource.com/skia.git/+log/af2f73c1bbd3..ef6bc4d7c581

2021-10-11 skia-autoroll@skia-public.iam.gserviceaccount.com Roll Dawn from a1e0aff8b8e2 to 9a8099eb8bee (2 revisions)
2021-10-11 skia-autoroll@skia-public.iam.gserviceaccount.com Roll Chromium from 64ed0bfb2eb7 to 1ab99fc6c07f (472 revisions)

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 djsollen@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: Id139627e9a6736e9e8b9c687f0d8ed8d8f8e29d1