How to get window title bar font ^size^ ?

FROM : Jerry Krinock
DATE : Sun Nov 25 07:21:57 2007

NSFont provides:

+ (NSFont *)titleBarFontOfSize:(float)fontSize

Just what I need to get the font used in window title bars!  But, 
uhhh, what do I give for the fontSize argument?  I know it looks like 
about 13, but how do I get a "correct, supported, future-proof" answer?

(The reason why I'm doing this is to place a little icon to the left 
of the title, so I need to know how big it is.  With lots of code, 
I've gotten it all to work...handling resizing was really fun.  But I 
have to hard-code that stupid font size.)

When I log the subviews of the window, I get the red button, the 
yellow button, the green button and the main contentView.  I was 
hoping to get some kind of text "view" that would be the window title, 
but apparently it's not a "view".

Thanks for any tips,

Jerry Krinock