This method returns an accessible child which contains the coordinate at (x, y) in screen pixels.
nsIAccessible getChildAtPoint( in long aX, in long aY );
- [in] Accessible's X-coordinate.
- [out] Accessible's Y-coordinate.
Returns an accessible child at given (x, y) coordinate.
If the point is in the current accessible but not in a child, the current accessible will be returned. If the point is in neither the current accessible or a child, then
NULL will be returned.