Moved creation of AudioDecoderFactory to inside PeerConnectionFactory.

webrtc/media/engine/webrtcmediaengine.h

Index: webrtc/media/engine/webrtcmediaengine.h
diff --git a/webrtc/media/engine/webrtcmediaengine.h b/webrtc/media/engine/webrtcmediaengine.h
index 19b7d222f2ea9c548b160e6fc2b7baac31c5fed6..c37d244b624b8adb1829388e55ed86806ae14333 100644
--- a/webrtc/media/engine/webrtcmediaengine.h
+++ b/webrtc/media/engine/webrtcmediaengine.h
@@ -31,8 +31,10 @@ class WebRtcMediaEngineFactory {
  public:
   static MediaEngineInterface* Create(
       webrtc::AudioDeviceModule* adm,
-      WebRtcVideoEncoderFactory* encoder_factory,
-      WebRtcVideoDecoderFactory* decoder_factory);
+      const rtc::scoped_refptr<webrtc::AudioDecoderFactory>&
+          audio_decoder_factory,
+      WebRtcVideoEncoderFactory* video_encoder_factory,
+      WebRtcVideoDecoderFactory* video_decoder_factory);
 };
 
 // Verify that extension IDs are within 1-byte extension range and are not