Fold AudioEncoderMutable into AudioEncoder

webrtc/modules/audio_coding/main/interface/audio_coding_module.h

Index: webrtc/modules/audio_coding/main/interface/audio_coding_module.h
diff --git a/webrtc/modules/audio_coding/main/interface/audio_coding_module.h b/webrtc/modules/audio_coding/main/interface/audio_coding_module.h
index 387632e0f44b1b8dba37eb8ae8428bb5c2ba3bfb..f2972e712c9072ca02d93f6ca495e422b747dca1 100644
--- a/webrtc/modules/audio_coding/main/interface/audio_coding_module.h
+++ b/webrtc/modules/audio_coding/main/interface/audio_coding_module.h
@@ -28,7 +28,7 @@ struct CodecInst;
 struct WebRtcRTPHeader;
 class AudioFrame;
 class RTPFragmentationHeader;
-class AudioEncoderMutable;
+class AudioEncoder;
 class AudioDecoder;
 
 #define WEBRTC_10MS_PCM_AUDIO 960  // 16 bits super wideband 48 kHz
@@ -225,7 +225,7 @@ class AudioCodingModule {
   // Registers |external_speech_encoder| as encoder. The new encoder will
   // replace any previously registered speech encoder (internal or external).
   virtual void RegisterExternalSendCodec(
-      AudioEncoderMutable* external_speech_encoder) = 0;
+      AudioEncoder* external_speech_encoder) = 0;
 
   ///////////////////////////////////////////////////////////////////////////
   // int32_t SendCodec()