[rust png] Use Rust-based Skia APIs: skia

This CL is part of a bigger change to stop using `libpng`-based Skia
APIs (e.g. `SkPngDecoder` or `SkPngEncoder`) and instead use equivalent
Rust-based Skia APIs (e.g. `SkPngRustDecoder` or `SkPngRustEncoder`).

This CL has been created by `git cl split`.  The original, not-yet-split
CL can be found at https://crrev.com/c/6931171.

This CL was uploaded by git cl split.

R=fmalita@chromium.org

Bug: 443128323
Change-Id: I8b8a1d247b787c7f582d4bb92513e624f9fab412
AX-Relnotes: n/a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6944815
Auto-Submit: Łukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: Kaylee Lubick <kjlubick@chromium.org>
Commit-Queue: Kaylee Lubick <kjlubick@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1515217}