Requires getting permission from the user to get "detailed" support.
Also enables users to go fullscreen on specific monitors.
Exposes platform-specific orientation API.
Most functionality depends on browser support, currently only Chromium.
- Internal: Fix dropping `Notifier` without sending a result causing `Future`s to never complete. This should never happen anyway, but now we get a panic instead of nothing if we hit a bug.
- Internal: Remove a bunch of `unwrap()`s that aren't required when correctly using `MainThreadMarker`.
- `Window::canvas()` is now able to return a reference instead of an owned value.
Extracted from #3801.
