Connect viewport adjustments to child focus adjustments (#1192155)
    
    When we use GtkScrolledWindow with non-natively scrollable widgets, the
    scroll adjustments on the intermediate viewport need to be connected to
    the focus adjustments on non-scrollable container in order for the
    viewport to automatically scroll on keyboard navigation events. Normally
    this is done automatically by gtk, but adding silent surprises in the
    middle of the widget hierarchy breaks glade so glade requires the
    viewport be explicit, and glade does not allow one to change any of the
    adjustment settings we need to get to. See
    https://bugzilla.gnome.org/show_bug.cgi?id=744721
    
    I am not optimistic about glade changing things quickly or ever so let's
    just work around it and have things work a little nicer.