Provide GVariant "packing" for complex GtkWidget types

[Allan LeSage]

As with autopilot-qt, not every GtkWidget fits directly into GVariant notation (like JSON formatting), and some types have to be "packed" so that they can be expressed as such. For an indicator, e.g., GtkCheckMenuItem needs to be interpreted for its 'active' property to be expressed as true or false to autopilot. Thomi has demonstrated this in autopilot-qt; we may crib his work but also I see an opportunity to apply this generally in Variant.cpp.

[Martin Pitt (pitti)]

Allan, can you please explain what you mean by this? GtkCheckMenuItem's "active" property is a simple bool, I guess that shouldn't cause any trouble? I found two cases where simple-typed properties don't work, for properties which are enum types (bug 1193342) and for properties which refer to other GObjects such as GtkTextView's "buffer" property which points to a GtkTextBuffer (bug 1194371). Are these two special cases of this bug, or did you mean something else?

[Martin Pitt (pitti)]

Setting to incomplete until I actually understand what is meant here. Alan will most likely not work on this one, but I will. I'd like to start with understanding the problem here and write a test for it.

[Martin Pitt (pitti)]

Allan, this morning I discovered and filed bug 1194763, about not being able to select_{single,many}() on int or bool properties. Does that happen to be what you mean, i. e. are these duplicate bugs?