As it turns out, SkPath already behaves the way we need for SVG and HTML
canvas elements. Less work for us, yay! This removes a 5% item from the
profile when scrolling on https://imdb.com/
Note that there's a tiny screenshot test expectation change due to
minor antialiasing differences when we no longer do our redundant
subpath modifications.
`aa_translation` is something we inherited from times when
AntiAliasingPainter was a thing. This change replaces it by applying
offset directly to path.
Canvas text painting needs to support per-glyph font fallbacks, which
means we can't hand over responsibility for text shaping to Skia and
instead need to extract glyph paths from our own shaped GlyphRun.
CSS filters work similarly to canvas filters, so it makes sense to have
Gfx::Filter that can be used by both libraries in an analogous way
as Gfx::Color.
