cursor surfaces are not scaled on HiDPI displays

Affected version

Ubuntu 20.04 (mutter 3.36.1), Wayland

Bug summary

On HiDPI displays with scale >1 (e.g. most commonly 2), wl_surfaces are automatically scaled up by the output scale factor. This excludes cursor surfaces which stay at the 1.0 scale and are therefore tiny compared to the rest of the wayland client and the desktop.

This might as well be a feature request, but since window and cursor surfaces are scaled inconsistently in different ways I see this as a bug.

Steps to reproduce

1. run GNOME Shell on a HiDPI display with scale 2
2. run weston-terminal

What happened

Window surfaces are upscaled by factor 2 but the cursor surface stays at factor 1 and is therefore half the size of the cursor as used by the desktop.

What did you expect to happen

I expected that cursor surfaces are upscaled by factor 2, in the same way in which all other client surfaces are scaled up.

A client can manually request a cursor surface at the scaled size, but since all other surfaces are scaled automatically we would expect that this applies to all client surfaces, including the cursor.

Relevant logs, screenshots, screencasts etc.