Reland 15721002: Hook up the device selection to the WebAudio live audio

content/renderer/media/webrtc_audio_device_impl.h

 // Copyright 2013 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.
 
 #ifndef CONTENT_RENDERER_MEDIA_WEBRTC_AUDIO_DEVICE_IMPL_H_
 #define CONTENT_RENDERER_MEDIA_WEBRTC_AUDIO_DEVICE_IMPL_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/threading/thread_checker.h"
 #include "content/common/content_export.h"
 #include "content/renderer/media/webrtc_audio_capturer.h"
 #include "content/renderer/media/webrtc_audio_device_not_impl.h"
 #include "content/renderer/media/webrtc_audio_renderer.h"
 #include "media/base/audio_capturer_source.h"
 #include "media/base/audio_renderer_sink.h"
 
 // A WebRtcAudioDeviceImpl instance implements the abstract interface
 // webrtc::AudioDeviceModule which makes it possible for a user (e.g. webrtc::
 // VoiceEngine) to register this class as an external AudioDeviceModule (ADM).
 // Then WebRtcAudioDeviceImpl::SetSessionId() needs to be called to set the
-// session id that tells which device to use. The user can either get the
-// session id from the MediaStream or use a value of 1 (AudioInputDeviceManager
-// ::kFakeOpenSessionId), the later will open the default device without going
-// through the MediaStream. The user can then call WebRtcAudioDeviceImpl::
-// StartPlayout() and WebRtcAudioDeviceImpl::StartRecording() from the render
-// process to initiate and start audio rendering and capturing in the browser
-// process. IPC is utilized to set up the media streams.
+// session id that tells which device to use. The user can then call
+// WebRtcAudioDeviceImpl::StartPlayout() and
+// WebRtcAudioDeviceImpl::StartRecording() from the render process to initiate
+// and start audio rendering and capturing in the browser process. IPC is
+// utilized to set up the media streams.
 //
 // Usage example:
 //
 //   using namespace webrtc;
 //
 //   {
 //      scoped_refptr<WebRtcAudioDeviceImpl> external_adm;
 //      external_adm = new WebRtcAudioDeviceImpl();
-//      external_adm->SetSessionId(1);
+//      external_adm->SetSessionId(session_id);
 //      VoiceEngine* voe = VoiceEngine::Create();
 //      VoEBase* base = VoEBase::GetInterface(voe);
 //      base->Init(external_adm);
 //      int ch = base->CreateChannel();
 //      ...
 //      base->StartReceive(ch)
 //      base->StartPlayout(ch);
 //      base->StartSending(ch);
 //      ...
 //      <== full-duplex audio session with AGC enabled ==>
@@ skipping 329 matching lines @@
   // Stores latest microphone volume received in a CaptureData() callback.
   // Range is [0, 255].
   uint32_t microphone_volume_;
 
   DISALLOW_COPY_AND_ASSIGN(WebRtcAudioDeviceImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_WEBRTC_AUDIO_DEVICE_IMPL_H_