Support multichannel audio stream more than 2 in MediaStreamDestinationNode

third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.h

Index: third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.h
diff --git a/third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.h b/third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.h
index f8bd9fe773706db49db2226bf0ffcc8bf2f56696..a753be127e472531b8007dd89a8acd872abc8641 100644
--- a/third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.h
+++ b/third_party/WebKit/Source/modules/webaudio/MediaStreamAudioDestinationNode.h
@@ -46,6 +46,9 @@ public:
 
     // AudioHandler.
     void process(size_t framesToProcess) override;
+    void setChannelCount(unsigned long, ExceptionState&) override;
+
+    unsigned long maxChannelCount() const;
 
 private:
     MediaStreamAudioDestinationHandler(AudioNode&, size_t numberOfChannels);
@@ -55,6 +58,8 @@ private:
     // This Persistent doesn't make a reference cycle.
     Persistent<MediaStream> m_stream;
     Persistent<MediaStreamSource> m_source;
+
+    // This internal mix bus functions as a up/down mixing buffer.

[Raymond Toy, 2015/11/20 14:47:19]

This isn't quite descriptive enough. I think it should say it for mixing the
input to the actual number of channels in the destination.

[hongchan, 2015/11/20 18:02:59]

Done.

     RefPtr<AudioBus> m_mixBus;
 };