DnD surfaces are to small with scale 200% and no 'scale-monitor-framebuffer' set
How to reproduce:
- use Mutter git master, Wayland session
- do not set 'scale-monitor-framebuffer'
- set the scale to 200%
- open nautilus and drag around some files
Observation: Dragged icons are too small, half the size they should be
I think this is a regression from !537 (merged), which by itself is correct, however.