Define Point for Bentley-Ottmann

Change-Id: I4a262500b54636eeae8baa1d249b35ed8ffce93d
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/743239
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
7 files changed