SkMatrix: get rid of AggregateMatrix

Change-Id: I9bb7b1f0f238937b59539d1b60e0f9b106498201
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/215444
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
2 files changed