[PATCH wayland/weston 0/7] drag-and-drop progress notification and actions

[Carlos Garnacho]

Hey,

Here's another batch of the drag-and-drop fixes, this time all together
because the last weston patches relies on both being in place. Overall
there's just small wording changes to the previous patches. A small
overview of the patches:

- wayland 1/2 and weston 1/5: Implement drag-and-drop progress notification,
  so the drag source gets to know when the drag destination is done with
  data transfers, or whether there was no accepting destination when the
  drop was performed.

  These are crucial to avoid leaks in the drag source, because it currently
  has no means to know any of both situations, so there's no natural place
  to free the allocated data related to the drag operation.

  In the context of DnD actions, those are also needed because likewise
  we have no natural place to perform the final delete in "move" operations.

- wayland 2/2 and weston 2/5: Implement drag-and-drop actions, so it is
  possible to make drag source and destination agree on one, the compositor
  can optionally induce specific actions to be selected, always given those
  are in the set agreed by source/destination.

- weston 3/5 to 5/5: Turn weston-dnd into more of a real world example,
  the choices made of defaulting to move, preemptively deleting the dragged
  item and allowing deletion of items by just dragging and dropping on the
  background make a nice demo, but a misguiding one if it demos the only
  way in which the current deficiencies in the protocol are not made evident.

  These patches make it a lot more similar to what GTK+ wants (and I assume
  other toolkits), it is my hope that it helps see how badly we need to
  shape drag-and-drop up to have something usable.

Cheers,
  Carlos