Is this a “good behavior” trip ?
Japan and Russia have a few foreign policy objectives in common, including the containing of China's hegemony, the free flow of fossil fuels (out of Russia, into Japan), squashing jihadi terrorism, and co-operation in Pacific trawling.
Since none of this counteracts anything that (should be) American foreign policy, a tri-partite summit would make sense, some time after Trump moves into the White House. If Hillary! somehow moves back instead, Japan might begin to play Russia against America for its own self-preservation, both political and economic.