Make DashOp a non-legacy GrMeshDrawOp.

Change-Id: I84ee3c64a5af8889e9a122cbc08d70ed6b25fbab
Reviewed-on: https://skia-review.googlesource.com/22210
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
5 files changed