Move more atlas functionality from GrSmallPathRenderer to GrSmallPathAtlasMgr

After this CL the GrSmallPathAtlasMgr is almost all ready to be moved
to be a flush-time entity.

This is pulled out of the omnibus CL: (Split the small path renderer into record-time and flush-time pieces)

Change-Id: Ie6a2196a640ce9be7a1e1c6d7bbdfd41413c42d0
Reviewed-by: Jim Van Verth <>
Commit-Queue: Robert Phillips <>
4 files changed