Add support for external decoders in ACM

webrtc/modules/audio_coding/main/acm2/acm_receive_test_oldapi.h

Index: webrtc/modules/audio_coding/main/acm2/acm_receive_test_oldapi.h
diff --git a/webrtc/modules/audio_coding/main/acm2/acm_receive_test_oldapi.h b/webrtc/modules/audio_coding/main/acm2/acm_receive_test_oldapi.h
index 5e5ff9a0a0e90028b6378f5560ec271e23b9e6ce..8e80ca79b5c96f4dc9c46fa95fed7c8aa5574c68 100644
--- a/webrtc/modules/audio_coding/main/acm2/acm_receive_test_oldapi.h
+++ b/webrtc/modules/audio_coding/main/acm2/acm_receive_test_oldapi.h
@@ -17,6 +17,7 @@
 
 namespace webrtc {
 class AudioCodingModule;
+class AudioDecoder;
 struct CodecInst;
 
 namespace test {
@@ -44,6 +45,11 @@ class AcmReceiveTestOldApi {
   // files.
   void RegisterNetEqTestCodecs();
 
+  int RegisterExternalReceiveCodec(int rtp_payload_type,
+                                   AudioDecoder* external_decoder,
+                                   int sample_rate_hz,
+                                   int num_channels);
+
   // Runs the test and returns true if successful.
   void Run();