k_();
    },

    appendDumpDotsTrack_() {
      const items = tr.ui.tracks.buildMemoryLetterDots(this.memoryDumps_);
      if (!items) return;

      const track = new tr.ui.tracks.LetterDotTrack(this.viewport);
      track.heading = 'Memory Dumps';
      track.items = items;
      Polymer.dom(this).appendChild(track);
    },

    appendUsedMemoryTrack_() {
      const tracks = [];
      const perProcessSeries =
          tr.ui.tracks.buildGlobalUsedMemoryChartSeries(this.memoryDumps_);
      if (perProces