Initial implementation of a GPU path renderer that draws antialiased
paths by counting coverage in an offscreen buffer.
Initially disabled until it has had time to soak.
Bug: skia:
Change-Id: I003d8cfdf8dc62641581b5ea2dc4f0aa00108df6
Reviewed-on: https://skia-review.googlesource.com/21541
Commit-Queue: Chris Dalton <csmartdalton@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
