Makes sure we use stream.ended in one place.

modules/RTC/LocalStream.js

  * @param stream original WebRTC stream object to which 'onended' handling
  *               will be added.
  */
-function implementOnEndedHandling(stream) {
+function implementOnEndedHandling(localStream) {
+    var stream = localStream.getOriginalStream();
     var originalStop = stream.stop;
     stream.stop = function () {
         originalStop.apply(stream);
-        if (!stream.ended) {
+        if (localStream.isActive()) {
             stream.ended = true;
             stream.onended();
         }
         });
 
     if (RTCBrowserType.isFirefox()) {
-        implementOnEndedHandling(this.stream);
+        implementOnEndedHandling(this);
     }
 }
 
     if (this.isAudioStream()) {
         tracks = this.stream.getAudioTracks();
     } else {
-        if (this.stream.ended)
+        if (this.isActive())
             return true;
         tracks = this.stream.getVideoTracks();
     }
     return this.stream.getTracks()[0].id;
 };
 
+/**
+ * Checks whether the MediaStream is avtive/not ended.
+ * @returns {boolean} whether MediaStream is active.
+ */
+LocalStream.prototype.isActive = function () {
+    return !this.stream.ended;
+};
+
 module.exports = LocalStream;