### Describe what you were doing when the bug occurred:
1. I did profiling on a list, that gets updated on each pagination api call.
2. Once the profiling was done, I moved around in the Profiler to view the Flamegraph
3. Moving to second capture, the Profiler crashed.


**DevTools version**: 4.6.0-6cceaeb67

```
Component stack: in ec
    in div
    in div
    in div
    in So
    in Unknown
    in n
    in Unknown
    in div
    in div
    in rl
    in Ze
    in fn
    in Ga
    in _s
```
effectDuration,
            fiberActualDurations,
            fiberSelfDurations,
            passiveEffectDuration,
            priorityLevel,
            timestamp: commitTime,
            updaters,
          });
        });
        dataForRoots.push({
          commitData,
          displayName,
          initialTreeBaseDurations,
          rootID,
        });
      },
    );
    return {
      dataForRoots,
      rendererID,
    };
  }
  function startProfiling(shouldRecordChangeDescriptions: boolean) {
    if (isProfiling) {
      return;
    }
    recordChangeDescriptions = shouldRecordChangeDescriptions;
     Capture initial values as of the time profiling starts.
     It's important we snapshot both the durations and the id-to-root map,
     since either of these may change during the profiling session