code: function(chart) {
              var tooltipRefresh = chart.tooltip.refresh,
                  decorateTooltip = (this.processedData.xAxisType === 'time') ?
                          this.addTimeTooltipClasses.bind(this) : this.addTooltipClasses.bind(this);
  
              this.addDataClasses(chart);
              this.addAxisClasses(chart);
              if(chart.options.legend.enabled) {
                  this.addLegendClasses(chart);
              }
              chart.tooltip.refresh = function(point) {
                  tooltipRefresh(point);
                  decorateTooltip(chart);
              }.bind(this);
          }
docs: ////////////////////////////////////////////////////////////////////////// methods for adding testing metadata  no other code should rely on the classes added here!