Revert "ccpr: Simplify triangle corners"

This reverts commit 622650a1949f9a68793ac895d9fbadee7177d860.

Reason for revert: Going to try to improve AAA quality on curve corners

Original change's description:
> ccpr: Simplify triangle corners
> 
> Modifies triangle corner shaders to just approximate their coverage with
> linear values that ramp to zero at bloat vertices outside the triangle.
> 
> For the vertex backend, since corners now have the same fragment shader
> as the rest of the triangle, we fold them in with the other steps and
> draw triangles in a single pass.
> 
> The geometry backend still draws triangles in two passes, as there is
> not an apparent performance advantage in combining them.
> 
> Bug: skia:
> Change-Id: Ib4a89d793a3c706f734d0271875c8a3e5c87c49b
> Reviewed-on: https://skia-review.googlesource.com/112632
> Commit-Queue: Chris Dalton <csmartdalton@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

TBR=bsalomon@google.com,csmartdalton@google.com

Change-Id: I45e7b9d7d7f8452b28bd54ca1e90a1f046cb2462
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/113180
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
13 files changed