Revert of MediaStream audio object graph untangling and clean-ups.

content/renderer/media/webrtc/peer_connection_dependency_factory.cc

Index: content/renderer/media/webrtc/peer_connection_dependency_factory.cc
diff --git a/content/renderer/media/webrtc/peer_connection_dependency_factory.cc b/content/renderer/media/webrtc/peer_connection_dependency_factory.cc
index e4bef0bff1f181ba564755240fdb7fe83daa8ab1..eb49d9d0426883aa392e88f25947f6d8de574e0a 100644
--- a/content/renderer/media/webrtc/peer_connection_dependency_factory.cc
+++ b/content/renderer/media/webrtc/peer_connection_dependency_factory.cc
@@ -9,8 +9,6 @@
 #include <utility>
 #include <vector>
 
-#include "base/bind.h"
-#include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/logging.h"
@@ -190,8 +188,8 @@
   HarmonizeConstraintsAndEffects(&constraints,
                                  &device_info.device.input.effects);
 
-  scoped_ptr<WebRtcAudioCapturer> capturer = CreateAudioCapturer(
-      render_frame_id, device_info, audio_constraints, source_data);
+  scoped_refptr<WebRtcAudioCapturer> capturer(CreateAudioCapturer(
+      render_frame_id, device_info, audio_constraints, source_data));
   if (!capturer.get()) {
     const std::string log_string =
         "PCDF::InitializeMediaStreamAudioSource: fails to create capturer";
@@ -203,7 +201,7 @@
     // be called multiple times which is likely also a bug.
     return false;
   }
-  source_data->SetAudioCapturer(std::move(capturer));
+  source_data->SetAudioCapturer(capturer.get());
 
   // Creates a LocalAudioSource object which holds audio options.
   // TODO(xians): The option should apply to the track instead of the source.
@@ -536,17 +534,19 @@
     const blink::WebMediaStreamTrack& track) {
   blink::WebMediaStreamSource source = track.source();
   DCHECK_EQ(source.getType(), blink::WebMediaStreamSource::TypeAudio);
-  MediaStreamAudioSource* source_data = MediaStreamAudioSource::From(source);
-
+  DCHECK(!source.remote());
+  MediaStreamAudioSource* source_data =
+      static_cast<MediaStreamAudioSource*>(source.getExtraData());
+
+  scoped_refptr<WebAudioCapturerSource> webaudio_source;
   if (!source_data) {
     if (source.requiresAudioConsumer()) {
       // We're adding a WebAudio MediaStream.
       // Create a specific capturer for each WebAudio consumer.
-      CreateWebAudioSource(&source);
-      source_data = MediaStreamAudioSource::From(source);
-      DCHECK(source_data->webaudio_capturer());
+      webaudio_source = CreateWebAudioSource(&source);
+      source_data = static_cast<MediaStreamAudioSource*>(source.getExtraData());
     } else {
-      NOTREACHED() << "Local track missing MediaStreamAudioSource instance.";
+      NOTREACHED() << "Local track missing source extra data.";
       return;
     }
   }
@@ -561,22 +561,10 @@
   // TODO(xians): Merge |source| to the capturer(). We can't do this today
   // because only one capturer() is supported while one |source| is created
   // for each audio track.
-  scoped_ptr<WebRtcLocalAudioTrack> audio_track(
-      new WebRtcLocalAudioTrack(adapter.get()));
-
-  // Start the source and connect the audio data flow to the track.
-  //
-  // TODO(miu): This logic will me moved to MediaStreamAudioSource (or a
-  // subclass of it) in soon-upcoming changes.
-  audio_track->Start(base::Bind(&MediaStreamAudioSource::StopAudioDeliveryTo,
-                                source_data->GetWeakPtr(),
-                                audio_track.get()));
-  if (source_data->webaudio_capturer())
-    source_data->webaudio_capturer()->Start(audio_track.get());
-  else if (source_data->audio_capturer())
-    source_data->audio_capturer()->AddTrack(audio_track.get());
-  else
-    NOTREACHED();
+  scoped_ptr<WebRtcLocalAudioTrack> audio_track(new WebRtcLocalAudioTrack(
+      adapter.get(), source_data->GetAudioCapturer(), webaudio_source.get()));
+
+  StartLocalAudioTrack(audio_track.get());
 
   // Pass the ownership of the native local audio track to the blink track.
   blink::WebMediaStreamTrack writable_track = track;
@@ -588,25 +576,48 @@
   blink::WebMediaStreamSource source = track.source();
   DCHECK_EQ(source.getType(), blink::WebMediaStreamSource::TypeAudio);
   DCHECK(source.remote());
-  DCHECK(MediaStreamAudioSource::From(source));
+  DCHECK(source.getExtraData());
 
   blink::WebMediaStreamTrack writable_track = track;
   writable_track.setExtraData(
       new MediaStreamRemoteAudioTrack(source, track.isEnabled()));
 }
 
-void PeerConnectionDependencyFactory::CreateWebAudioSource(
+void PeerConnectionDependencyFactory::StartLocalAudioTrack(
+    WebRtcLocalAudioTrack* audio_track) {
+  // Start the audio track. This will hook the |audio_track| to the capturer
+  // as the sink of the audio, and only start the source of the capturer if
+  // it is the first audio track connecting to the capturer.
+  audio_track->Start();
+}
+
+scoped_refptr<WebAudioCapturerSource>
+PeerConnectionDependencyFactory::CreateWebAudioSource(
     blink::WebMediaStreamSource* source) {
   DVLOG(1) << "PeerConnectionDependencyFactory::CreateWebAudioSource()";
 
+  scoped_refptr<WebAudioCapturerSource>
+      webaudio_capturer_source(new WebAudioCapturerSource(*source));
   MediaStreamAudioSource* source_data = new MediaStreamAudioSource();
-  source_data->SetWebAudioCapturer(
-      make_scoped_ptr(new WebAudioCapturerSource(source)));
+
+  // Use the current default capturer for the WebAudio track so that the
+  // WebAudio track can pass a valid delay value and |need_audio_processing|
+  // flag to PeerConnection.
+  // TODO(xians): Remove this after moving APM to Chrome.
+  if (GetWebRtcAudioDevice()) {
+    source_data->SetAudioCapturer(
+        GetWebRtcAudioDevice()->GetDefaultCapturer());
+  }
 
   // Create a LocalAudioSource object which holds audio options.
   // SetLocalAudioSource() affects core audio parts in third_party/Libjingle.
   source_data->SetLocalAudioSource(CreateLocalAudioSource(NULL).get());
   source->setExtraData(source_data);
+
+  // Replace the default source with WebAudio as source instead.
+  source->addAudioConsumer(webaudio_capturer_source.get());
+
+  return webaudio_capturer_source;
 }
 
 scoped_refptr<webrtc::VideoTrackInterface>
@@ -747,7 +758,7 @@
   }
 }
 
-scoped_ptr<WebRtcAudioCapturer>
+scoped_refptr<WebRtcAudioCapturer>
 PeerConnectionDependencyFactory::CreateAudioCapturer(
     int render_frame_id,
     const StreamDeviceInfo& device_info,