show cubic error-vectors anchored on pt(s) of max deviation

Bug: skia:
Change-Id: I59a6a218ddbf46bc5d7ebea6303701b5182eafa7
Reviewed-on: https://skia-review.googlesource.com/121427
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
1 file changed