(systraceLines) {
    const events = JSON.stringify({
      traceEvents: [],
      systemTraceEvents: SYSTRACE_CLOCK_SYNC + '\n' + systraceLines.join('\n')
    });
    const model = tr.c.TestUtils.newModelWithEvents([events]);
    // Fix missing process names.
    for (const pid in model.processes) {
      const process = model.processes[pid];
      if (process.name !== undefined) continue;
      if (process.threads[pid] !== undefined) {
        process.name = process.threads[pid].name;
      }
    }
    re