Add inner bounds of round rect function

Change-Id: I6d48d4aebfffcf106ab22b511e43f76a4f8972c6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/284276
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
3 files changed