Convert GrOvalOpFactory from GrLegacyMeshDrawOp to GrMeshDrawOp using GrSimpleDrawOpHelper.

Change-Id: Ib9f59ddf1c2c3f2bd0004ae16f842e52f45df8c9
Reviewed-on: https://skia-review.googlesource.com/16832
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
5 files changed