canvas: Remove as much usage of font-kit as possible (servo#32758)

Do font selection using Servo's font backend, which is shared with the
rest of layout. In addition, delay the creation of the `font-kit` font
until just before rendering with `raqote`. The idea is that when
`raqote` is no longer used, we can drop the `font-kit` dependency.

This change has the side-effect of fixing text rendering in canvas,
adding support for font fallback in canvas, and also correcting a bug in
font selection with size overrides.

Signed-off-by: Martin Robinson <[email protected]>
Co-authored-by: Mukilan Thiyagarajan <[email protected]>

components/canvas/Cargo.toml

@@ -15,6 +15,7 @@ webgl_backtrace = ["canvas_traits/webgl_backtrace"]
 xr-profile = ["webxr-api/profile", "time"]
 
 [dependencies]
+app_units = { workspace = true }
 bitflags = { workspace = true }
 byteorder = { workspace = true }
 canvas_traits = { workspace = true }
@@ -30,15 +31,18 @@ log = { workspace = true }
 lyon_geom = "1.0.4"
 net_traits = { workspace = true }
 num-traits = { workspace = true }
+parking_lot = { workspace = true }
 pathfinder_geometry = "0.5"
 pixels = { path = "../pixels" }
+range = { path = "../range" }
 raqote = "0.8.4"
 servo_arc = { workspace = true }
 sparkle = { workspace = true }
 style = { workspace = true }
 style_traits = { workspace = true }
 surfman = { workspace = true }
 time = { workspace = true, optional = true }
+unicode-script = { workspace = true }
 webrender = { workspace = true }
 webrender_api = { workspace = true }
 webrender_traits = { workspace = true }