Skip making a surface context when doing threaded SW paths

Bug: skia:
Change-Id: I4f78abc836f22a216e94a47cb2a7414edccbd2b6
Reviewed-on: https://skia-review.googlesource.com/44201
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed