I'm trying to roll my own overlay toggle tree with embedded legend graphics, and I'm finding that if I generate an esri/dijit/Legend, after startup() I then have access to a legendResponse object on the layer (right below layerInfos) which has all the legend images and label info. Without generating a legend it's not present. Is there a way to retrieve the content of legendResponse without actually generating a legend?
The only alternative I see is to hit each sublayer by <service url>/<id>/legend and save the drawingInfo.symbol piece, but this is not a lightweight task if the dynamic service has a ton of layers.
My buddy working on an iOS implementation has AGSMapServiceInfo.retrieveLegendInfo which does this. Digging into the TOC code, it looks like it's using http://www.arcgis.com/sharing/tools/legend/rest/ service to return this. Is this something we can install on our own arcgis server?