[rust png] Support converting `png::FrameControl` into Skia equivalent.

This CL adds support for converting `png::FrameControl` into `SkFrame`
properties.

Note that `SkPngRustCodec` doesn't yet support traversing the input
stream to discover `fcTL` chunks that may be present *after* the initial
`IDAT` chunks.  This means that the new code from this CL may light up
when `fcTL` appears before `IDAT`, but the new code won't really be
load-bearing until follow-up CLs tweak `onGetFrameCount` to discover
metadata of additional frames.

Bug: chromium:356922876
Change-Id: Ic0b3819939ff4a69a199d5f94414959a5a325726
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/904575
Commit-Queue: Ɓukasz Anforowicz <lukasza@google.com>
Reviewed-by: Daniel Dilan <danieldilan@google.com>
3 files changed