x-dnd-get-drop-width-height
x-dnd-get-drop-width-height is a compiled Lisp function in `x-dnd.el
'.
(x-dnd-get-drop-width-height FRAME W ACCEPT)
Return the width/height to be sent in a XDndStatus message.
FRAME is the frame and W is the window where the drop happened.
If ACCEPT is nil return 0 (empty rectangle),
otherwise if W is a window, return its width/height,
otherwise return the frame width/height.