Bug 1274221 - Test that multiple tracks of the same source all end when in the same stream. r=jib

MozReview-Commit-ID: 64T6I4RDrKH

--HG--
extra : rebase_source : 0b19990a9e4a7d2748f2757a067a1c2e7ce4b703
extra : intermediate-source : 30c253e762c6aab5eea21b94c2efa8d033572931
extra : source : b9a09fe46c5e1adc8659070a8f4f60d9e09b7311

dom/media/tests/mochitest/test_getUserMedia_trackEnded.html

@@ -27,8 +27,13 @@
     // navigated away (see bug 1269400 for details).
     return new Promise((resolve, reject) =>
         iframe.contentDocument.gUM({audio: true, video: true}, resolve, reject))
-      .then(s => stream = s)
-      .then(() => {
+      .then(s => {
+        // We're cloning a stream containing identical tracks (an original
+        // and its clone) to test that ended works both for originals
+        // clones when they're both owned by the same MediaStream.
+        // (Bug 1274221)
+        stream = new MediaStream([].concat(s.getTracks(), s.getTracks())
+                                   .map(t => t.clone())).clone();
         var allTracksEnded = Promise.all(stream.getTracks().map(t => {
           info("Set up ended handler for track " + t.id);
           return haveEvent(t, "ended", wait(5000))