      // receiving the click event.
      event.stopPropagation();
    },

    openHistogram_() {
      this.isHistogramOpen = true;
      tr.b.Timing.instant('histogram-set-table-cell', 'open');
    },

    closeHistogram_() {
      this.isHistogramOpen = false;
      tr.b.Timing.instant('histogram-set-table-cell', 'close');
    },

    updateContents_() {
      const isOpen = this.isHistogramOpen;

      this.$.empty.style.display = 'none';
      this.$.unmergeable.style.display = 'none';
      this.$.sca