DevTools performance page doesn't detect jank between frames

In this example, the running app (Wonderous in profile mode) visibly janks, but there are no janky frames in the DevTools performance page. Upon looking deeper into the timeline trace, it is clear that there is a large gap of latency between two frames:

How is a user supposed to debug the jank at this point? How can we help them understand what could be causing the latency between frames?

CC @chinmaygarde @dnfield @iskakaushik @jonahwilliams for ideas.