Use non-linear blending flag in raster pipeline blitter

BUG=skia:

Change-Id: I00b52e6de3b46b7d26c1df2aa63c521b6c7ece2d
Reviewed-on: https://skia-review.googlesource.com/8526
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
5 files changed