MediaRecorder: make EventListener and stop if receiving on{add,remove}track from WebMediaStream

third_party/WebKit/LayoutTests/fast/mediastream/MediaStream-add-remove-tracks.html

Index: third_party/WebKit/LayoutTests/fast/mediastream/MediaStream-add-remove-tracks.html
diff --git a/third_party/WebKit/LayoutTests/fast/mediastream/MediaStream-add-remove-tracks.html b/third_party/WebKit/LayoutTests/fast/mediastream/MediaStream-add-remove-tracks.html
index 9d406b29b43d47ffb8ecbbaf676cdb5920042bf3..91dacff45d367a58e580610164c33f01b1374269 100644
--- a/third_party/WebKit/LayoutTests/fast/mediastream/MediaStream-add-remove-tracks.html
+++ b/third_party/WebKit/LayoutTests/fast/mediastream/MediaStream-add-remove-tracks.html
@@ -45,10 +45,6 @@ function tryRemoveTrack(stream, track) {
     }
 }
 
-function shouldNotFire() {
-    testFailed("\"addtrack\" or \"removetrack\" events should not fire as a result of local addTrack() or removeTrack() operations.");
-}
-
 function onStreamInactive() {
     testPassed('Stream1 inactive.');
     shouldBeFalse('stream1.active');
@@ -79,8 +75,8 @@ function gotStream2(s) {
     shouldBe('stream2.getVideoTracks().length', '1');
     shouldBe('stream2.getTracks().length', '2');
 
-    stream1.onaddtrack = shouldNotFire;
-    stream1.onremovetrack = shouldNotFire;
+    stream1.onaddtrack = function() {};

[perkj_chrome, 2016/01/11 08:21:20]

This does not seem right according to spec. (it was correct from the beginning)
http://www.w3.org/TR/mediacapture-streams/#event-mediastream-addtrack

+    stream1.onremovetrack = function() {};
 
     // remove a track of each kind
     audioTrack = stream1.getAudioTracks()[0];