Summary:
Added selection source concept to onSelect callback. This allows us to only autoscroll the tree when selection source is the visualiser. We had feedback that the horizontal autoscrolling whilst using the tree was unhelpful.
A side benefit of selection source is better tracking of how people use kb, tree vs visualiser to select things
Changelog: UIDebugger only autoscroll horizontally when selecting via the visualiser
Reviewed By: lblasa
Differential Revision: D47334078
fbshipit-source-id: d7eadddb8d3d0fd428d5c294b2dccc2f1efa5a95