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

third_party/WebKit/Source/modules/mediarecorder/MediaRecorder.h

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MediaRecorder_h
 #define MediaRecorder_h
 
 #include "core/dom/ActiveDOMObject.h"
 #include "core/events/EventTarget.h"
 #include "modules/EventTargetModules.h"
@@ skipping 61 matching lines @@
     void stop() override;
     bool hasPendingActivity() const override { return !m_stopped; }
 
     // WebMediaRecorderHandlerClient
     void writeData(const char* data, size_t length, bool lastInSlice) override;
     void onError(const WebString& message) override;
 
     DECLARE_VIRTUAL_TRACE();
 
 private:
+    class TrackEventListener;
+
     MediaRecorder(ExecutionContext*, MediaStream*, const MediaRecorderOptions&, ExceptionState&);
 
     void createBlobEvent(Blob*);
 
     void stopRecording();
     void scheduleDispatchEvent(PassRefPtrWillBeRawPtr<Event>);
     void dispatchScheduledEvent();
 
     Member<MediaStream> m_stream;
     String m_mimeType;
     bool m_stopped;
     bool m_ignoreMutedMedia;
 
     State m_state;
 
     OwnPtr<BlobData> m_blobData;
 
     OwnPtr<WebMediaRecorderHandler> m_recorderHandler;
+    RefPtrWillBePersistent<EventListener> m_addOrRemoveTrackListener;
 
     AsyncMethodRunner<MediaRecorder> m_dispatchScheduledEventRunner;
     WillBeHeapVector<RefPtrWillBeMember<Event>> m_scheduledEvents;
 };
 
 } // namespace blink
 
 #endif // MediaRecorder_h