extract GrDrawDrawableSubRun

This interface will be shared between the GrTextBlob, and Slug.

Change-Id: Idac5fb1ba64a60458098fc02bd7e473c31525bb2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/475542
Commit-Queue: Herb Derby <herb@google.com>
Auto-Submit: Herb Derby <herb@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed