minor SkRegion include edits

name or rename parameters

TBR=reed@google.com

Bug: skia:6818
Change-Id: I04637a25869b3512e241e157528cd794a53481a2
Reviewed-on: https://skia-review.googlesource.com/145720
Reviewed-by: Cary Clark <caryclark@skia.org>
Commit-Queue: Cary Clark <caryclark@skia.org>
Auto-Submit: Cary Clark <caryclark@skia.org>
1 file changed