add GM to compare atlas and vertices

Bug: skia:6571
Change-Id: Ic97101c4623c7557eb33f69796232ed51a89af7e
Reviewed-on: https://skia-review.googlesource.com/14621
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Mike Reed <reed@google.com>
1 file changed