use pathbuilder

Change-Id: I4b40107b45cd829595e89d75e19fd063acee4221
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/311106
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
19 files changed