Sure Mir will/should support client-side decorations.
The best suggestion I have right now is:
1. You set mir_surface_type_freestyle
2. Wait for Mir shells to honour the surface type and not wrap extra decorations around it.
In future we might have some additional attribute you could set for client-side decorations instead of mir_surface_type_freestyle. Not sure...
Sure Mir will/should support client-side decorations.
The best suggestion I have right now is: type_freestyle
1. You set mir_surface_
2. Wait for Mir shells to honour the surface type and not wrap extra decorations around it.
In future we might have some additional attribute you could set for client-side decorations instead of mir_surface_ type_freestyle. Not sure...