address brianosman feedback

comments are here
https://skia-review.googlesource.com/c/23061/16

Some bugs pointed out are in the generation
code and will take more time to work out;
the changes here I could make immediately

R=brianosman@google.com
TBR=reed@google.com

Change-Id: I7497e5a220a5df597d0e881acd3747ee17856cd1
Reviewed-on: https://skia-review.googlesource.com/26901
Commit-Queue: Cary Clark <caryclark@skia.org>
Reviewed-by: Cary Clark <caryclark@skia.org>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed