Mark time gaps in frame list

If the graph at the top of the Performance tab, which shows the list of frames, could show a physical gap when the corresponding frames were not sequential (e.g. were more than 50ms apart with no FrameRequestPending in the interval), it would be helpful as a way to distinguish different animations. For example, if I load an app, then wait, then tap a button, then wait, then hit a button, I would love to see the three separate animations slightly separated from each other in that frame selector.