Another fix for dash line thickness.

Use the device space offset from the dash centerline for
antialiasing in y direction.

Bug: chromium:1049028

Change-Id: Ib6363579680d05cbf1fe34795695422baeca7065
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/288764
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
2 files changed