Add externs for CartoDB response

externs/cartodb.js

@@ -0,0 +1,34 @@
+/**
+ * @externs
+ */
+
+
+
+/**
+ * @constructor
+ */
+var CartoDBLayerInfo = function() {};
+
+
+/**
+ * @type {string}
+ */
+CartoDBLayerInfo.prototype.layergroupid;
+
+
+/**
+ * @type {string}
+ */
+CartoDBLayerInfo.prototype.updated_at;
+
+
+/**
+ * @type {Object}
+ */
+CartoDBLayerInfo.prototype.metadata;
+
+
+/**
+ * @type {{http: string, https: string}}
+ */
+CartoDBLayerInfo.prototype.cdn_url;