Parametric SkPath oval/rect/rrect starting point

Extend the SkPath API to allow specifying the contour starting point.

This will allow removing the explicit cubic code from Blink/Path.

BUG=chromium:315277
R=reed@google.com,caryclark@google.com

Review URL: https://codereview.chromium.org/1452203002
2 files changed