bug#31020: 27.0; Please provide a way to know about menu-bar wrapping

[Drew Adams]

Enhancement request.

When a frame is narrower than the text in the
menu-bar, that text is wrapped.  And yet the value of frame parameter
`menu-bar-lines' is not increased (which is good).

It would be good to be able to know (from Elisp) how many "visual"
(effective) menu-bar lines there are currently, that is, how many times
the menu-bar text is wrapped.  (It is typically wrapped zero or one
time, producing text that appears visually to be two lines.)


In GNU Emacs 27.0.50 (build 3, x86_64-w64-mingw32)
 of 2018-03-21
Repository revision: e70d0c9e66d7a8609450b2889869d16aeb0363b5
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install -C 'CFLAGS=-O2 -static -g3''