Remove duplicate function.

static/cosmopolite.js

@@ -116,6 +116,10 @@ var Cosmopolite = function(opt_urlPrefix, opt_namespace, opt_trackingID) {
    * Weep for all our souls.
    */
   this.eventTarget_ = document.createDocumentFragment();
+
+  /**
+   * @type {function(string, function(Event))}
+   */
   this.addEventListener =
       this.eventTarget_.addEventListener.bind(this.eventTarget_);
   this.removeEventListener =
@@ -554,16 +558,6 @@ Cosmopolite.prototype.currentProfile = function() {
 };
 
 
-/**
- * @see https://www.cosmopolite.org/reference#isConnected
- * @return {boolean}
- * @const
- */
-Cosmopolite.prototype.isConnected = function() {
-  return (this.channelState_ == Cosmopolite.ChannelState_.OPEN);
-};
-
-
 /**
  * @see https://www.cosmopolite.org/reference#pin_method
  * @param {Cosmopolite.typeSubjectLoose} subject