Use half floats for non-normalized color in GrTextureOp

Bug: skia:
Change-Id: Ie681369ef4b1d3d43c326da684afde9ce6d08486
Reviewed-on: https://skia-review.googlesource.com/c/171726
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
10 files changed