Add path renderer options to viewer GUI

BUG=skia:

Change-Id: I248ba081f0229d7fcf2071009076acc88b80b076
Reviewed-on: https://skia-review.googlesource.com/9088
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Jim Van Verth <jvanverth@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
4 files changed