Use the current default capture for the webaudio track to get the correct delay value

content/renderer/media/media_stream_dependency_factory.cc

 // Copyright (c) 2012 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 "content/renderer/media/media_stream_dependency_factory.h"
 
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 267 matching lines @@
 
 scoped_refptr<webrtc::AudioTrackInterface>
 MediaStreamDependencyFactory::CreateNativeAudioMediaStreamTrack(
     const blink::WebMediaStreamTrack& track) {
   blink::WebMediaStreamSource source = track.source();
   DCHECK_EQ(source.type(), blink::WebMediaStreamSource::TypeAudio);
   MediaStreamAudioSource* source_data =
       static_cast<MediaStreamAudioSource*>(source.extraData());
 
   scoped_refptr<WebAudioCapturerSource> webaudio_source;
-  if (!source_data) {
+  scoped_refptr<WebRtcAudioCapturer> capturer;
+  if (source_data) {
+    capturer = source_data->GetAudioCapturer();
+  } else {
     if (source.requiresAudioConsumer()) {
       // We're adding a WebAudio MediaStream.
       // Create a specific capturer for each WebAudio consumer.
       webaudio_source = CreateWebAudioSource(&source);
       source_data =
           static_cast<MediaStreamAudioSource*>(source.extraData());
+
+      // 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())
+        capturer = GetWebRtcAudioDevice()->GetDefaultCapturer();
     } else {
       // TODO(perkj): Implement support for sources from
       // remote MediaStreams.
       NOTIMPLEMENTED();
       return NULL;
     }
   }
 
   return CreateLocalAudioTrack(track,
-                               source_data->GetAudioCapturer(),
+                               capturer,
                                webaudio_source.get(),
                                source_data->local_audio_source());
 }
 
 scoped_refptr<webrtc::VideoTrackInterface>
 MediaStreamDependencyFactory::CreateNativeVideoMediaStreamTrack(
     const blink::WebMediaStreamTrack& track) {
   DCHECK(track.extraData() == NULL);
   blink::WebMediaStreamSource source = track.source();
   DCHECK_EQ(source.type(), blink::WebMediaStreamSource::TypeVideo);
@@ skipping 521 matching lines @@
 }
 
 void MediaStreamDependencyFactory::EnsureWebRtcAudioDeviceImpl() {
   if (audio_device_)
     return;
 
   audio_device_ = new WebRtcAudioDeviceImpl();
 }
 
 }  // namespace content