bug#19576: write-file writes the wrong buffer

[martin rudalics]

>> No particular reason.  But note that ‘delete-other-windows-internal’ may
>> bypass window_resize_apply, so in that particular case we have to
>> manually make sure that the window_sizes_changed flag gets set.  I hope
>> this is the only case where it matters.
>
> Would you mind doing this on the master branch, please?

It might have interesting consequences.  Presumably, you expect that
this way we'll be finally able to run ‘window-size-change-functions’ if
and only if the size of windows really changed.  Correct?

martin