Revert "Revert "mark SkRasterPipelineBlitter final""

Revert "Revert "mark SkRasterPipelineBlitter final""

This reverts commit b5b26a9d2999825ba8f405b8c37d33d49a529369.

Reason for revert: this one's probably fine too

Original change's description:
> Revert "mark SkRasterPipelineBlitter final"
>
> This reverts commit 317a1857f80ffc18d591dd6b1ac0988184b1ed2b.
>
> Reason for revert: Valgrind requires reverting ancestor commit.
>
> Original change's description:
> > mark SkRasterPipelineBlitter final
> >
> > This devirtualizes the call from blitAntiH to blitH,
> > and makes sure no future self calls will be virtual.
> >
> > Change-Id: I2a277bbc1450a96e07794791792d59e5f806bde0
> > Reviewed-on: https://skia-review.googlesource.com/17418
> > Commit-Queue: Mike Klein <mtklein@chromium.org>
> > Reviewed-by: Mike Klein <mtklein@chromium.org>
> >
>
> TBR=mtklein@chromium.org,herb@google.com,reed@google.com
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
>
> Change-Id: Ic726fd6b9bf18c397812ecc256353ab4a0a336c5
> Reviewed-on: https://skia-review.googlesource.com/17522
> Reviewed-by: Brian Osman <brianosman@google.com>
> Commit-Queue: Brian Osman <brianosman@google.com>
>

TBR=mtklein@chromium.org,herb@google.com,reviews@skia.org,brianosman@google.com,reed@google.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: Ic27fbfaab9d040a1ef49d596350649096b908ea3
Reviewed-on: https://skia-review.googlesource.com/17528
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>