319d0bb679
We now additionally send:
- wl_data_offer.source_actions
- wl_data_source.action
- wl_data_offer.action
- wl_data_source.drop_performed
- wl_data_source.drag_finished
The protocol changes allow for compositors to implement different policies
when chosing the action, mutter uses this to reimplement the same behavior
that GTK+ traditionally had:
- Alt/Control/Shift modifiers change the chosen action to
ask/copy/move respectively
- Drags with middle button start out as "ask" by default
As mutter now also grabs the keyboard and unsets the window focus for these
purposes, the window focus is restored after the drag operation has
finished.