Describe what you were doing when the bug occurred:
1. Clicking back to go back through the frames following a profile session. I think I got to zero and then clicked it again and then it errored

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DevTools version: 4.8.2-fed4ae024

Call stack: at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17661:26)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)
    at getCommitTree (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:17710:30)

Component stack: at CommitRankedAutoSizer (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:31963:48)
    at div
    at div
    at div
    at SettingsModalContextController (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:26139:23)
    at Profiler_Profiler (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:33363:48)
    at ErrorBoundary (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:27172:5)
    at PortaledContent (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:27303:32)
    at div
    at div
    at ProfilerContextController (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:30463:23)
    at TreeContextController (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:22538:23)
    at SettingsContextController (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:23040:27)
    at ModalDialogContextController (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:28328:23)
    at DevTools_DevTools (chrome-extension://fmkadmapgofadopljbjfkapdkoienihi/build/main.js:33797:21)
parentID,
      treeBaseDuration: ((dataForRoot.initialTreeBaseDurations.get(
        id,
      ): any): number),
      type: node.type,
    });
    node.children.forEach(childID =>
      recursivelyInitializeTree(childID, id, nodes, dataForRoot),
    );
  }
}
function updateTree(
  commitTree: CommitTree,
  operations: Array<number>,
): CommitTree {
  
  const nodes = new Map(commitTree.nodes);
  
  const getClonedNode = (id: number): CommitTreeNode => {
    const clonedNode = ((Object.assign(
      {},
      nodes.get(id),
    ): any): CommitTreeNode);
    nodes.set(id, clonedNode);
    return clonedNode;
  };
  let i = 2;
  let id: number = ((null: any): number);
  
  const stringTable = [