This CL undoes most of the changes from http://review.skia.org/451739
and http://review.skia.org/451741 as these changes opened up a threading
can of worms that is probably not solvable. I no longer have a use case
for the new dsl::Start APIs.
Change-Id: Icf0a86364d258ea3bbf0d18bbdbd130ef590c02f
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/452097
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: John Stiles <johnstiles@google.com>
Auto-Submit: John Stiles <johnstiles@google.com>
11101181b9