Add layers code to share link

app/assets/javascripts/application.js

@@ -114,6 +114,10 @@ function updatelinks(loc, zoom, layers, bounds, object) {
   }
 }
 
+function minZoomAlert() {
+    alert(I18n.t("javascripts.site." + name + "_zoom_alert")); return false;
+}
+
 function getShortUrl(map) {
   return (window.location.hostname.match(/^www\.openstreetmap\.org/i) ?
           'http://osm.org/go/' : '/go/') +
@@ -129,14 +133,11 @@ function getUrl(map) {
         querystring.stringify({
             lat: center.lat,
             lon: center.lng,
-            zoom: zoom
+            zoom: zoom,
+            layers: map.getLayersCode()
         });
 }
 
-function minZoomAlert() {
-    alert(I18n.t("javascripts.site." + name + "_zoom_alert")); return false;
-}
-
 // Called to create a short code for the short link.
 function makeShortCode(map) {
     var zoom = map.getZoom(),
@@ -175,6 +176,12 @@ function makeShortCode(map) {
     return str;
 }
 
+// generate a cookie-safe string of map state
+function cookieContent(map) {
+  var center = map.getCenter().wrap();
+  return [center.lng, center.lat, map.getZoom(), map.getLayersCode()].join('|');
+}
+
 /*
  * Forms which have been cached by rails may have the wrong
  * authenticity token, so patch up any forms with the correct