Bug 1208373 - Test that ended tracks that are cloned are also ended. r=jib

MozReview-Commit-ID: 4YU31TK0Mdf

--HG--
extra : rebase_source : d56d39f2f7071a67bf99ed4cb4fd3b26ee51cc4f
extra : intermediate-source : 816141c9f43f5b98d7b1489e1fd61196f2feb570
extra : source : 0d4ff0ff0dac011751329d23122e8e55e37ee3f7

dom/media/tests/mochitest/test_getUserMedia_mediaStreamTrackClone.html

@@ -52,7 +52,10 @@
 
       var test = createMediaElement('video', 'testClonePlayback');
       var playback = new MediaStreamPlayback(test, cloneStream);
-      return playback.playMediaWithMediaStreamTracksStop(false);
+      return playback.playMediaWithMediaStreamTracksStop(false)
+        .then(() => info("Testing that clones of ended tracks are ended"))
+        .then(() => cloneStream.clone().getTracks().forEach(t =>
+          is(t.readyState, "ended", "Track " + t.id + " should be ended")));
     })
     .then(() => getUserMedia({audio: true, video: true})).then(stream => {
       info("Test adding many track clones to the original stream");