async function renderHistory() {
  const dom_history = document.querySelector('#idle-history');
  dom_history.innerHTML = '';
  const { history_log } = await chrome.storage.session.get(['history_log']);
  if (!history_log) {
    return;
  }

  for (let i = 0; i < history_log.length; i++) {
    const data = history_log[i];
    renderItem(data['state'], data['time'], dom_history);
  }
}
Render the data gathered by the background service worker - should show a log
of "active" states.