diff -r 000000000000 -r 6474c204b198 content/media/webaudio/MediaStreamAudioDestinationNode.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/media/webaudio/MediaStreamAudioDestinationNode.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,122 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "MediaStreamAudioDestinationNode.h"
+#include "nsIDocument.h"
+#include "mozilla/dom/MediaStreamAudioDestinationNodeBinding.h"
+#include "AudioNodeEngine.h"
+#include "AudioNodeStream.h"
+#include "DOMMediaStream.h"
+#include "TrackUnionStream.h"
+
+namespace mozilla {
+namespace dom {
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(MediaStreamAudioDestinationNode, AudioNode, mDOMStream)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(MediaStreamAudioDestinationNode)
+NS_INTERFACE_MAP_END_INHERITING(AudioNode)
+
+NS_IMPL_ADDREF_INHERITED(MediaStreamAudioDestinationNode, AudioNode)
+NS_IMPL_RELEASE_INHERITED(MediaStreamAudioDestinationNode, AudioNode)
+
+static const int MEDIA_STREAM_DEST_TRACK_ID = 2;
+static_assert(MEDIA_STREAM_DEST_TRACK_ID != AudioNodeStream::AUDIO_TRACK,
+              "MediaStreamAudioDestinationNode::MEDIA_STREAM_DEST_TRACK_ID must be a different value than AudioNodeStream::AUDIO_TRACK");
+
+class MediaStreamDestinationEngine : public AudioNodeEngine {
+public:
+  MediaStreamDestinationEngine(AudioNode* aNode, ProcessedMediaStream* aOutputStream)
+    : AudioNodeEngine(aNode)
+    , mOutputStream(aOutputStream)
+  {
+    MOZ_ASSERT(mOutputStream);
+  }
+
+  virtual void ProcessBlock(AudioNodeStream* aStream,
+                            const AudioChunk& aInput,
+                            AudioChunk* aOutput,
+                            bool* aFinished) MOZ_OVERRIDE
+  {
+    *aOutput = aInput;
+    StreamBuffer::Track* track = mOutputStream->EnsureTrack(MEDIA_STREAM_DEST_TRACK_ID,
+                                                            aStream->SampleRate());
+    AudioSegment* segment = track->Get<AudioSegment>();
+    segment->AppendAndConsumeChunk(aOutput);
+  }
+
+  virtual size_t SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const MOZ_OVERRIDE
+  {
+    return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+  }
+
+private:
+  ProcessedMediaStream* mOutputStream;
+};
+
+// This callback is used to ensure that only the audio data for this track is audible
+static bool FilterAudioNodeStreamTrack(StreamBuffer::Track* aTrack)
+{
+  return aTrack->GetID() == MEDIA_STREAM_DEST_TRACK_ID;
+}
+
+MediaStreamAudioDestinationNode::MediaStreamAudioDestinationNode(AudioContext* aContext)
+  : AudioNode(aContext,
+              2,
+              ChannelCountMode::Explicit,
+              ChannelInterpretation::Speakers)
+  , mDOMStream(DOMAudioNodeMediaStream::CreateTrackUnionStream(GetOwner(),
+                                                               MOZ_THIS_IN_INITIALIZER_LIST(),
+                                                               DOMMediaStream::HINT_CONTENTS_AUDIO))
+{
+  TrackUnionStream* tus = static_cast<TrackUnionStream*>(mDOMStream->GetStream());
+  MOZ_ASSERT(tus == mDOMStream->GetStream()->AsProcessedStream());
+  tus->SetTrackIDFilter(FilterAudioNodeStreamTrack);
+
+  MediaStreamDestinationEngine* engine = new MediaStreamDestinationEngine(this, tus);
+  mStream = aContext->Graph()->CreateAudioNodeStream(engine, MediaStreamGraph::INTERNAL_STREAM);
+  mPort = tus->AllocateInputPort(mStream, 0);
+
+  nsIDocument* doc = aContext->GetParentObject()->GetExtantDoc();
+  if (doc) {
+    mDOMStream->CombineWithPrincipal(doc->NodePrincipal());
+  }
+}
+
+size_t
+MediaStreamAudioDestinationNode::SizeOfExcludingThis(MallocSizeOf aMallocSizeOf) const
+{
+  // Future:
+  // - mDOMStream
+  size_t amount = AudioNode::SizeOfExcludingThis(aMallocSizeOf);
+  amount += mPort->SizeOfIncludingThis(aMallocSizeOf);
+  return amount;
+}
+
+size_t
+MediaStreamAudioDestinationNode::SizeOfIncludingThis(MallocSizeOf aMallocSizeOf) const
+{
+  return aMallocSizeOf(this) + SizeOfExcludingThis(aMallocSizeOf);
+}
+
+void
+MediaStreamAudioDestinationNode::DestroyMediaStream()
+{
+  AudioNode::DestroyMediaStream();
+  if (mPort) {
+    mPort->Destroy();
+    mPort = nullptr;
+  }
+}
+
+JSObject*
+MediaStreamAudioDestinationNode::WrapObject(JSContext* aCx)
+{
+  return MediaStreamAudioDestinationNodeBinding::Wrap(aCx, this);
+}
+
+}
+}