Use GrVertexWriter and support half-float colors in rrect ops

Bug: skia:
Change-Id: Id33ead33cdcd8c4e6b034a33ba0e555a1374b2d4
Reviewed-on: https://skia-review.googlesource.com/c/175426
Reviewed-by: Chris Dalton <csmartdalton@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
1 file changed