fix(RemoteVideo): change hasVideoStarted logic

We used to rely on 'currentTime' of the video element, but we execute
'updateView' from the 'onplay' callback and on fast machines it may
happen that the value is 0 even though the video has just started.

modules/UI/videolayout/RemoteVideo.js

@@ -29,6 +29,14 @@ function RemoteVideo(user, VideoLayout, emitter) {
     this.setDisplayName();
     this.flipX = false;
     this.isLocal = false;
+    /**
+     * The flag is set to <tt>true</tt> after the 'onplay' event has been
+     * triggered on the current video element. It goes back to <tt>false</tt>
+     * when the stream is removed. It is used to determine whether the video
+     * playback has ever started.
+     * @type {boolean}
+     */
+    this.wasVideoPlayed = false;
 }
 
 RemoteVideo.prototype = Object.create(SmallVideo.prototype);
@@ -218,6 +226,10 @@ RemoteVideo.prototype.removeRemoteStreamElement = function (stream) {
     var select = $('#' + elementID);
     select.remove();
 
+    if (isVideo) {
+        this.wasVideoPlayed = false;
+    }
+
     console.info((isVideo ? "Video" : "Audio") +
                  " removed " + this.id, select);
 
@@ -316,6 +328,7 @@ RemoteVideo.prototype.waitForPlayback = function (streamElement, stream) {
     // Register 'onplaying' listener to trigger 'videoactive' on VideoLayout
     // when video playback starts
     var onPlayingHandler = function () {
+        self.wasVideoPlayed = true;
         self.VideoLayout.videoactive(streamElement, self.id);
         streamElement.onplaying = null;
         // Refresh to show the video
@@ -325,15 +338,13 @@ RemoteVideo.prototype.waitForPlayback = function (streamElement, stream) {
 };
 
 /**
- * Checks whether or not video stream exists and has started for this
- * RemoteVideo instance. This is checked by trying to select video element in
- * this container and checking if 'currentTime' field's value is greater than 0.
+ * Checks whether the video stream has started for this RemoteVideo instance.
  *
- * @returns {*|boolean} true if this RemoteVideo has active video stream running
+ * @returns {boolean} true if this RemoteVideo has a video stream for which
+ * the playback has been started.
  */
 RemoteVideo.prototype.hasVideoStarted = function () {
-    var videoSelector = this.selectVideoElement();
-    return videoSelector.length && videoSelector[0].currentTime > 0;
+    return this.wasVideoPlayed;
 };
 
 RemoteVideo.prototype.addRemoteStreamElement = function (stream) {