wayland: Add synchronized requests to WlDisplay
This series moves the buffer commit in waylandsink and gtkwaylandsink from the streaming thread to the display thread (thread that dispatches wayland display queue).
Since there are significant similarities between the handling in the two sinks, the bulk of this logic is moved into GstWlWindow.
In order to handle synchronization between the display thread and the streaming thread, synchronized versions
of wl_display_sync()
and wl_callback_destroy()
are added to GstWlDisplay
Closes #1711 (closed)
Edited by Damian Hobson-Garcia