Injectable audio encoders: WebRtcVoiceEngine and company

webrtc/media/engine/webrtcvoiceengine.h

Index: webrtc/media/engine/webrtcvoiceengine.h
diff --git a/webrtc/media/engine/webrtcvoiceengine.h b/webrtc/media/engine/webrtcvoiceengine.h
index 33e53f1f394cfaa4cf1e86b3a3f6260921ae29bf..992ed2d12f7859a897c31f923d52cae5e95aa63f 100644
--- a/webrtc/media/engine/webrtcvoiceengine.h
+++ b/webrtc/media/engine/webrtcvoiceengine.h
@@ -27,6 +27,7 @@
 #include "webrtc/media/base/rtputils.h"
 #include "webrtc/media/engine/webrtccommon.h"
 #include "webrtc/media/engine/webrtcvoe.h"
+#include "webrtc/modules/audio_coding/codecs/audio_encoder_factory.h"
 #include "webrtc/modules/audio_processing/include/audio_processing.h"
 #include "webrtc/pc/channel.h"
 
@@ -113,13 +114,15 @@ class WebRtcVoiceEngine final : public webrtc::TraceCallback  {
   webrtc::AudioProcessing* apm();
   webrtc::voe::TransmitMixer* transmit_mixer();
 
-  AudioCodecs CollectRecvCodecs() const;
+  AudioCodecs CollectCodecs(
+      const std::vector<webrtc::AudioCodecSpec>& specs) const;
 
   rtc::ThreadChecker signal_thread_checker_;
   rtc::ThreadChecker worker_thread_checker_;
 
   // The audio device manager.
   rtc::scoped_refptr<webrtc::AudioDeviceModule> adm_;
+  rtc::scoped_refptr<webrtc::AudioEncoderFactory> encoder_factory_;
   rtc::scoped_refptr<webrtc::AudioDecoderFactory> decoder_factory_;
   // Reference to the APM, owned by VoE.
   webrtc::AudioProcessing* apm_ = nullptr;
@@ -284,7 +287,8 @@ class WebRtcVoiceMediaChannel final : public VoiceMediaChannel,
   std::map<uint32_t, WebRtcAudioReceiveStream*> recv_streams_;
   std::vector<webrtc::RtpExtension> recv_rtp_extensions_;
 
-  webrtc::AudioSendStream::Config::SendCodecSpec send_codec_spec_;
+  rtc::Optional<webrtc::AudioSendStream::Config::SendCodecSpec>
+      send_codec_spec_;
 
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(WebRtcVoiceMediaChannel);
 };