Revert of Add SkSpecialImage::extractSubset & NewFromPixmap (patchset #5 id:80001 of https://codereview.chromium.org/1787883002/ )

Reason for revert:
Need to wean ImagePixelLocker.h off of SkAutoPixmapStorage :(

Original issue's description:
> Add SkSpecialImage::extractSubset & NewFromPixmap
>
> This is calved off of: https://codereview.chromium.org/1785643003/ (Switch SkBlurImageFilter over to new onFilterImage interface)
>
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1787883002
>
> Committed: https://skia.googlesource.com/skia/+/250581493a0859987e482810879e85e5ac2dc002

TBR=bsalomon@google.com,reed@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1808833002
19 files changed