remove SkPicture_none.cpp

I happened to notice that SkPicture_none.cpp no longer compiles.

    ...
    src/core/SkPicture_none.cpp:101:44: error: out-of-line definition of
    'CreateProc' does not match any declaration in 'SkPictureImageFilter'
    sk_sp<SkFlattenable> SkPictureImageFilter::CreateProc(SkReadBuffer& buffer) {
    ...

This leads me to conclude that it cannot be in active use.

Change-Id: I92a4daa3c7d5d7889c4f841b578c9c691525c1cc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/235216
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>
5 files changed