Change SDFT to use a bulk api for the callback

Change-Id: I280b11d134c1b1b03f979cc80a087fe176f659e5
Reviewed-on: https://skia-review.googlesource.com/c/194425
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
1 file changed