bug#21100: 25.0.50; quit-restore-window should also retore width, not just height

[martin rudalics <rudalics@gmx.at>]

 >>> 1. Split the frame into two windows, one above the other.
 >>> 2. Make the bottom window very small.
 >>> 3. With point in the larger window, run `C-h f point RET'
 >>> 4. The bottom window increases in size to display the Help buffer.
 >>
 >> I can't reproduce that here.
 >
 > That's probably because your monitor is larger than my laptop's.
 >
 >> So what did you do to accomplish that resize?
 >
 > Try doing (set-face-attribute 'default nil :height 290)

That's no recipe, at least not with emacs -Q.  With emacs -Q this just
makes my frame much larger than my display.  Please try to give me a
recipe with emacs -Q.  Something's at work here which I don't understand
yet.

 > If the frame is large enough to fit two windows side-by-side, then the
 > help buffer will always be created in a new window to the right.

This contradicts your scenario where you say that the help buffer reuses
an already existing window.

 > However, if the font size is large enough that two windows do NOT fit
 > side by side in the frame, then the window is created below. In this
 > scenario, you get the behavior I described (i.e., if there's already a
 > window below the current one, it is reused by the help buffer and it
 > is expanded if necessary).

It's just that I don't know _why_ a reused window would be expanded.
Can you point me to where in the code this expansion takes place?

martin