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

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

 // 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.
 
 #include "modules/mediarecorder/MediaRecorder.h"
 
 #include "bindings/core/v8/Dictionary.h"
 #include "core/events/Event.h"
 #include "core/fileapi/Blob.h"
 #include "modules/EventTargetModules.h"
@@ skipping 18 matching lines @@
     case MediaRecorder::State::Paused:
         return "paused";
     }
 
     ASSERT_NOT_REACHED();
     return String();
 }
 
 } // namespace
 
+class MediaRecorder::TrackEventListener final : public EventListener {
+public:
+    static PassRefPtrWillBeRawPtr<TrackEventListener> create(blink::WebMediaRecorderHandlerClient* client)
+    {
+        return adoptRefWillBeNoop(new TrackEventListener(client));
+    }
+
+    bool operator==(const EventListener& other) const override
+    {
+        return this == &other;
+    }
+
+private:
+    TrackEventListener(blink::WebMediaRecorderHandlerClient* client)
+        : EventListener(JSEventListenerType)
+        , m_client(client)
+    {
+    }
+
+    void handleEvent(ExecutionContext* executionContext, Event*) override
+    {
+        m_client->onError("MediaStream got a Track added/removed");
+    }
+
+    blink::WebMediaRecorderHandlerClient* const m_client;
+};
+
 MediaRecorder* MediaRecorder::create(ExecutionContext* context, MediaStream* stream, ExceptionState& exceptionState)
 {
     MediaRecorder* recorder = new MediaRecorder(context, stream, MediaRecorderOptions(), exceptionState);
     recorder->suspendIfNeeded();
 
     return recorder;
 }
 
 MediaRecorder* MediaRecorder::create(ExecutionContext* context, MediaStream* stream,  const MediaRecorderOptions& options, ExceptionState& exceptionState)
 {
@@ skipping 20 matching lines @@
     // We deviate from the spec by not returning |UnsupportedOption|, see https://github.com/w3c/mediacapture-record/issues/18
     if (!m_recorderHandler) {
         exceptionState.throwDOMException(NotSupportedError, "No MediaRecorder handler can be created.");
         return;
     }
     ContentType contentType(m_mimeType);
     if (!m_recorderHandler->initialize(this, stream->descriptor(), contentType.type(), contentType.parameter("codecs"))) {
         exceptionState.throwDOMException(NotSupportedError, "Failed to initialize native MediaRecorder, the type provided " + m_mimeType + "is unsupported." );
         return;
     }
+
+    m_addOrRemoveTrackListener = TrackEventListener::create(this);
+    stream->addEventListener(EventTypeNames::addtrack, m_addOrRemoveTrackListener, false);
+    stream->addEventListener(EventTypeNames::removetrack, m_addOrRemoveTrackListener, false);
+
     m_stopped = false;
 }
 
 String MediaRecorder::state() const
 {
     return stateToString(m_state);
 }
 
 void MediaRecorder::start(ExceptionState& exceptionState)
 {
@@ skipping 176 matching lines @@
 
 DEFINE_TRACE(MediaRecorder)
 {
     visitor->trace(m_stream);
     visitor->trace(m_scheduledEvents);
     RefCountedGarbageCollectedEventTargetWithInlineData<MediaRecorder>::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }
 
 } // namespace blink