[LMP] Avoid rare use-after-free condition.
[LMP] IPath::PerformWProbe()
[LMP Potorchu] Expose the visual filter.
[LMP Potorchu] States can now be synced explicitly after ctor.
[LMP Potorchu] Change the visualizer with a probe.
[LMP Potorchu] EnumerateVisualizers() returns factory list.
[LMP Potorchu] Pass & change the factory to the VisBranch.
[LMP Potorchu] Handle previous visualization requests as well.