code: function(bounds, zoomChanged, dragging) {
          OpenLayers.Layer.prototype.moveTo.apply(this, arguments);
  
          if (zoomChanged || !this.drawn) {
              for(var i=0, len=this.markers.length; i<len; i++) {
                  this.drawMarker(this.markers[i]);
              }
              this.drawn = true;
          }
      }
docs: Method: moveTo
  
  Parameters:
  bounds - {<OpenLayers.Bounds>}
  zoomChanged - {Boolean}
  dragging - {Boolean}