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

third_party/WebKit/Source/modules/mediastream/MediaStream.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  * Copyright (C) 2011, 2012 Ericsson AB. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 188 matching lines @@
         m_videoTracks.append(track);
         break;
     }
     track->registerMediaStream(this);
     m_descriptor->addComponent(track->component());
 
     if (!active() && !track->ended()) {
         m_descriptor->setActive(true);
         scheduleDispatchEvent(Event::create(EventTypeNames::active));
     }
+    scheduleDispatchEvent(MediaStreamTrackEvent::create(EventTypeNames::addtrack, false, false, track));
 
     MediaStreamCenter::instance().didAddMediaStreamTrack(m_descriptor, track->component());
 }
 
 void MediaStream::removeTrack(MediaStreamTrack* track, ExceptionState& exceptionState)
 {
     if (!track) {
         exceptionState.throwDOMException(TypeMismatchError, "The MediaStreamTrack provided is invalid.");
         return;
     }
@@ skipping 14 matching lines @@
 
     if (pos == kNotFound)
         return;
     track->unregisterMediaStream(this);
     m_descriptor->removeComponent(track->component());
 
     if (active() && emptyOrOnlyEndedTracks()) {
         m_descriptor->setActive(false);
         scheduleDispatchEvent(Event::create(EventTypeNames::inactive));
     }
+    scheduleDispatchEvent(MediaStreamTrackEvent::create(EventTypeNames::removetrack, false, false, track));
 
     MediaStreamCenter::instance().didRemoveMediaStreamTrack(m_descriptor, track->component());
 }
 
 MediaStreamTrack* MediaStream::getTrackById(String id)
 {
     for (MediaStreamTrackVector::iterator iter = m_audioTracks.begin(); iter != m_audioTracks.end(); ++iter) {
         if ((*iter)->id() == id)
             return iter->get();
     }
@@ skipping 158 matching lines @@
     visitor->trace(m_audioTracks);
     visitor->trace(m_videoTracks);
     visitor->trace(m_descriptor);
     visitor->trace(m_scheduledEvents);
     RefCountedGarbageCollectedEventTargetWithInlineData<MediaStream>::trace(visitor);
     ContextLifecycleObserver::trace(visitor);
     MediaStreamDescriptorClient::trace(visitor);
 }
 
 } // namespace blink