This reverts commit 76af907676.
The behavioral change described in the migration guide
has now been made optional with new scrolled window API,
so no need to mention this in the migration guide.
The effect of transitions-enabled=true can now be
achieved using gtk_popover_popup/popdown and the effect
of transitions-enabled=false can be achieved using
gtk_widget_show/hide.
https://bugzilla.gnome.org/show_bug.cgi?id=769706
The header bar currently ignores the expand property on its
children. This commit changes the code to honor that property.
It divvies up any free space and distributes it equally to packed
children (with any left over space given out a pixel at a time
on a first come, first serve basis).
This commit also adds support for the title widget to be made
expandable.
It accomplishes this by using up the padding the title widget
is centered with.
https://bugzilla.gnome.org/show_bug.cgi?id=724332
