Reland of Simplify SkGpuBlurUtils::GaussianBlur method (patchset #1 id:1 of https://codereview.chromium.org/1956023002/ )

Reason for revert:
May not be as bad as was thought

Original issue's description:
> Revert of Simplify SkGpuBlurUtils::GaussianBlur method (patchset #2 id:20001 of https://codereview.chromium.org/1958603002/ )
>
> Reason for revert:
> Looks like it's causing some issues with the bleed_image GM.
>
> Original issue's description:
> > Simplify SkGpuBlurUtils::GaussianBlur method
> >
> > No one was using the canClobberSrc capability and moving the direct filtering case forward makes the rest of the logic simpler.
> >
> > Split out of: https://codereview.chromium.org/1959493002/ (Retract GrRenderTarget from SkGpuBlurUtils)
> >
> > GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1958603002
> >
> > Committed: https://skia.googlesource.com/skia/+/56a85e69a8d034e0fdee00e8207cda0a9da06fee
>
> TBR=bsalomon@google.com,robertphillips@google.com
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
>
> Committed: https://skia.googlesource.com/skia/+/67a58dcd4a1e79e5832161ae953526d27893aa61

TBR=bsalomon@google.com,jvanverth@google.com
# Not skipping CQ checks because original CL landed more than 1 days ago.

Review-Url: https://codereview.chromium.org/1961953002
6 files changed