Remove some unused SkPicture code

Change-Id: I720fb2c9464d341a53ac3cac836ef4266eb45429
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/696868
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
5 files changed