Delete FRAME, permanently eliminating it from use.
FRAME defaults to the selected frame.
A frame may not be deleted if its minibuffer is used by other frames.
Normally, you may not delete a frame if all other frames are invisible,
but if the second optional argument FORCE is non-nil, you may do so.
This function runs `delete-frame-functions' before actually
deleting the frame, unless the frame is a tooltip.
The functions are run with one argument, the frame to be deleted. (fn &optional FRAME FORCE)