      sample, sample.timestamp, sample.value, 0));
        valueRange.addValue(sample.value);
      }
      // Stretch min to max range over the top half of a chart for readability.
      const baseLine = Math.max(0, valueRange.min - valueRange.range);
      const axisY = new tr.ui.tracks.ChartSeriesYAxis(baseLine, valueRange.max);
      const chartSeries =
          [new tr.ui.tracks.ChartSeries(chartPoints, axisY,
              SYSTEM_MEMORY_CHART_RENDERING_CONFIG)];
      tracks.push({
        name: 'Sys