Describe what you were doing when the bug occurred:

Profiled the new FB. Scrolled down to tail loads.

---------------------------------------------
Please do not remove the text below this line
---------------------------------------------

DevTools version: 4.6.0-a2fb84beb

Call stack: at chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:345591
    at Array.map (<anonymous>)
    at chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:345397
    at Ai (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:32:62580)
    at zl (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:32:112694)
    at jc (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:32:104789)
    at Oc (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:32:104717)
    at Tc (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:32:104585)
    at gc (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:32:101042)
    at chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:32:47376

Component stack: at chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:344679
    at div
    at div
    at n (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:194307)
    at div
    at Cc (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:346311)
    at div
    at n (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:3:8163)
    at div
    at bc
    at div
    at div
    at div
    at Do (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:262081)
    at chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:364048
    at n (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:274563)
    at chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:277138
    at div
    at div
    at ol (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:323458)
    at Ze (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:205764)
    at pn (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:215038)
    at $a (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:292153)
    at ws (chrome-extension://dnjnjgbfilfphmojnmhliehogmojhclc/build/main.js:40:369231)
'var(--color-commit-gradient-3)',
  'var(--color-commit-gradient-4)',
  'var(--color-commit-gradient-5)',
  'var(--color-commit-gradient-6)',
  'var(--color-commit-gradient-7)',
  'var(--color-commit-gradient-8)',
  'var(--color-commit-gradient-9)',
];
export function prepareProfilingDataFrontendFromBackendAndStore(
  dataBackends: Array<ProfilingDataBackend>,
  operationsByRootID: Map<number, Array<Array<number>>>,
  snapshotsByRootID: Map<number, Map<number, SnapshotNode>>,
): ProfilingDataFrontend {
  const dataForRoots: Map<number, ProfilingDataForRootFrontend> = new Map();
  dataBackends.forEach(dataBackend => {
    dataBackend.dataForRoots.forEach(
      ({
        commitData,
        displayName,
        initialTreeBaseDurations,
        interactionCommits,
        interactions,
        rootID,
      }) => {
        const operations = operationsByRootID.get(rootID);
        if (operations == null) {
          throw Error(`Could not find profiling operations for root ${rootID}`);
        }
        const snapshots = snapshotsByRootID.get(rootID);
        if (snapshots == null) {