docs: function() {
        var isSecondaryImport = this.model.getClockSyncRecordsNamed(
            'ftrace_importer').length !== 0;
  
        var mSyncs = this.model_.getClockSyncRecordsNamed('monotonic');
        // If this is a secondary import, and no clock syncing records were
        // found, then abort the import. Otherwise, just skip clock alignment.
        if (mSyncs.length == 0)
          return isSecondaryImport ? undefined : 0;
  
        // Shift all the slice times based on the sync record.
        // TODO(skyostil): Compute a scaling factor if we have multiple clock sync
        // records.
        var sync = mSyncs[0].args;
        // NB: parentTS of zero denotes no times-shift; this is
        // used when user and kernel event clocks are identical.
        if (sync.parentTS == 0 || sync.parentTS == sync.perfTS)
          return 0;
        return sync.parentTS - sync.perfTS;
      }