Revert "Reland "Revert "Add arcs as a specialized geometry to GrShape."""

This reverts commit 580aee2fa4a57bf8208498fbc23acea04e16e092.

Bug: skia:7794
Change-Id: I9c2b923859c826dff58c22c529dc4e2ab4d0f186
Reviewed-on: https://skia-review.googlesource.com/124042
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
6 files changed