On macOS, support NSAccessibilityProtocol's accessibilitySelectedChildren
method [1] by retrieving the selected children via the
QAccessibleSelectionInterface introduced in commit
9d16d5e224.
This e.g. makes a "selected children" attribute show up
in "UI Browser" [2] for the item views in the "interview" example
(examples/widgets/itemviews/interview/interview.app/Contents/MacOS/interview)
and that one has an array containing the selected items as value.
Sample scenario:
1) run the interview example (examples/widgets/itemviews/interview/interview.app)
2) select "Item 1:0", "Item 2:0" and "Item 3:0" by left-clicking
on "Item 1:0" in the left view, then shift+clicking on "Item 3:0".
3) start UI Browser and navigate to the "group (group 1)" element
and check that the value of its "selected children" attribute is an
array containing the three selected items
[1] https://developer.apple.com/documentation/appkit/nsaccessibilityprotocol/1524672-accessibilityselectedchildren
[2] https://latenightsw.com/freeware/ui-browser/
Change-Id: Ic62f7fa82f2d01341a1dbc5ade2bd02c3ff99d9f
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>