proposed gn_to_bp fixes

in response to 5784

Change-Id: I3ad34a30743e7ffbd04767668c288a4f884eb19c
Reviewed-on: https://skia-review.googlesource.com/5732
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
2 files changed