https://bugzilla.gnome.org/show_bug.cgi?id=794842
This is to allow returning an error that can easily be sent as message to the application if the element needs it. Using this also allow ignoring errors. https://bugzilla.gnome.org/show_bug.cgi?id=766172
This will allow removing code duplication (hence bugs duplication). https://bugzilla.gnome.org/show_bug.cgi?id=727925