Return a FRAME's height in pixels.
If FRAME is omitted, the selected frame is used. The exact value
of the result depends on the window-system and toolkit in use:
In the Gtk+ version of Emacs, it includes only any window (including
the minibuffer or echo area), mode line, and header line. It does not
include the tool bar or menu bar.
With other graphical versions, it also includes the tool bar and the
menu bar.
For a text terminal, it includes the menu bar. In this case, the
result is really in characters rather than pixels (i.e., is identical
to `frame-height').
(fn &optional FRAME)