move blur and path attributes to key

Blur and stroke information were kept out of line with the key.
Make them part of the key, and update operator==.

Change-Id: I2e7669aae4e9c3243c078b039ae796a7e371ef8e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/315282
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
5 files changed