mestampToPoint === undefined) {
          idToTimestampToPoint[id] = timestampToPoint = new Array(dumpCount);
          for (let i = 0; i < dumpCount; i++) {
            const modelItem = memoryDumps[i];
            timestampToPoint[i] = new tr.ui.tracks.ChartPoint(
                modelItem, modelItem.start, 0);
          }
        }
        timestampToPoint[index].y += size;
        if (opt_name !== undefined) idToName[id] = opt_name;
      });
    });

    // Do not generate any chart series if no sizes 