Add some optimizations to PolyUtils

* Switch inset/offset code to use a linked list rather than an array
* Use std::set to store active edge list for IsSimplePolygon rather than array
* Pre-alloc the priority queue for IsSimplePolygon
* When adding radial curves, expand the array all at once rather than pushing
one at a time.

Bug: skia:
Change-Id: I692f8c29c500c41ec1d1be39d924d8a752676bf4
Reviewed-on: https://skia-review.googlesource.com/140787
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
4 files changed