MediaStream should fire ended event when all tracks are ended

Source/WebCore/Modules/mediastream/MediaStream.cpp

Index: Source/WebCore/Modules/mediastream/MediaStream.cpp
diff --git a/Source/WebCore/Modules/mediastream/MediaStream.cpp b/Source/WebCore/Modules/mediastream/MediaStream.cpp
index 5c388abaf3adef1737c2da3991627241004c40e7..471764716e49e2f7554b0f504b6de79dbc897a87 100644
--- a/Source/WebCore/Modules/mediastream/MediaStream.cpp
+++ b/Source/WebCore/Modules/mediastream/MediaStream.cpp
@@ -115,17 +115,23 @@ MediaStream::MediaStream(ScriptExecutionContext* context, PassRefPtr<MediaStream
     size_t numberOfAudioTracks = m_descriptor->numberOfAudioComponents();
     m_audioTracks.reserveCapacity(numberOfAudioTracks);
     for (size_t i = 0; i < numberOfAudioTracks; i++)
-        m_audioTracks.append(MediaStreamTrack::create(context, m_descriptor->audioComponent(i)));
+        m_audioTracks.append(MediaStreamTrack::create(context, m_descriptor->audioComponent(i), this));
 
     size_t numberOfVideoTracks = m_descriptor->numberOfVideoComponents();
     m_videoTracks.reserveCapacity(numberOfVideoTracks);
     for (size_t i = 0; i < numberOfVideoTracks; i++)
-        m_videoTracks.append(MediaStreamTrack::create(context, m_descriptor->videoComponent(i)));
+        m_videoTracks.append(MediaStreamTrack::create(context, m_descriptor->videoComponent(i), this));
 }
 
 MediaStream::~MediaStream()
 {
     m_descriptor->setClient(0);
+
+    for (size_t i = 0; i < m_audioTracks.size(); ++i)
+        m_audioTracks[i]->clearStream();
+
+    for (size_t i = 0; i < m_videoTracks.size(); ++i)
+        m_videoTracks[i]->clearStream();
 }
 
 bool MediaStream::ended() const
@@ -151,7 +157,7 @@ void MediaStream::addTrack(PassRefPtr<MediaStreamTrack> prpTrack, ExceptionCode&
         return;
 
     RefPtr<MediaStreamComponent> component = MediaStreamComponent::create(m_descriptor.get(), track->component()->source());
-    RefPtr<MediaStreamTrack> newTrack = MediaStreamTrack::create(scriptExecutionContext(), component.get());
+    RefPtr<MediaStreamTrack> newTrack = MediaStreamTrack::create(scriptExecutionContext(), component.get(), this);
 
     switch (component->source()->type()) {
     case MediaStreamSource::TypeAudio:
@@ -186,6 +192,7 @@ void MediaStream::removeTrack(PassRefPtr<MediaStreamTrack> prpTrack , ExceptionC
         size_t pos = m_audioTracks.find(track);
         if (pos != notFound) {
             m_audioTracks.remove(pos);
+            track->clearStream();
             m_descriptor->removeAudioComponent(track->component());
         }
         break;
@@ -194,6 +201,7 @@ void MediaStream::removeTrack(PassRefPtr<MediaStreamTrack> prpTrack , ExceptionC
         size_t pos = m_videoTracks.find(track);
         if (pos != notFound) {
             m_videoTracks.remove(pos);
+            track->clearStream();
             m_descriptor->removeVideoComponent(track->component());
         }
         break;
@@ -264,7 +272,7 @@ void MediaStream::addRemoteTrack(MediaStreamComponent* component)
 
     component->setStream(descriptor());
 
-    RefPtr<MediaStreamTrack> track = MediaStreamTrack::create(scriptExecutionContext(), component);
+    RefPtr<MediaStreamTrack> track = MediaStreamTrack::create(scriptExecutionContext(), component, this);
     switch (component->source()->type()) {
     case MediaStreamSource::TypeAudio:
         m_audioTracks.append(track);
@@ -304,6 +312,7 @@ void MediaStream::removeRemoteTrack(MediaStreamComponent* component)
 
     RefPtr<MediaStreamTrack> track = (*tracks)[index];
     tracks->remove(index);
+    track->clearStream();
     scheduleDispatchEvent(MediaStreamTrackEvent::create(eventNames().removetrackEvent, false, false, track));
 }
 
@@ -330,6 +339,18 @@ void MediaStream::scheduledEventTimerFired(Timer<MediaStream>*)
     events.clear();
 }
 
+void MediaStream::didEndTrack()

[eseidel, 2013/04/09 06:42:25]

If this dispatches synchronous javascript events, then this is a security
disaster waiting to happen. :)  It's not clear to me the behavior here. 
Synchronous javascript calls can tear down or re-arrange your world in arbitrary
ways. :)

[Li Yin, 2013/04/09 07:38:33]

didEndTrack is only checking whether the event should be triggered, if yes, it
calls existing function "streamEnded".
And streamEnded is using timer to trigger the event.

+{
+    for (size_t i = 0; i < m_audioTracks.size(); ++i)
+        if (!m_audioTracks[i]->ended())
+            return;
+
+    for (size_t i = 0; i < m_videoTracks.size(); ++i)
+        if (!m_videoTracks[i]->ended())
+            return;
+
+    streamEnded();
+}
 } // namespace WebCore
 
 #endif // ENABLE(MEDIA_STREAM)