code: function(bounds, zoomChanged, dragging) {
          var display = this.visibility;
          if (!this.isBaseLayer) {
              display = display && this.inRange;
          }
          this.display(display);
      }
docs: Method: moveTo
  
  Parameters:
  bounds - {<OpenLayers.Bounds>}
  zoomChanged - {Boolean} Tells when zoom has changed, as layers have to
  do some init work in that case.
  dragging - {Boolean}