allows us to remove SkCanvas::replayClips in future CL
BUG=skia:
Change-Id: I20c3700c8a331b4988fc1332702ff0e0565e94bc
Reviewed-on: https://skia-review.googlesource.com/9417
Reviewed-by: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Reed <reed@google.com>