WIP: Move the creation of AudioCodecFactory into PeerConnectionFactory.

webrtc/modules/audio_coding/acm2/audio_coding_module.cc

Index: webrtc/modules/audio_coding/acm2/audio_coding_module.cc
diff --git a/webrtc/modules/audio_coding/acm2/audio_coding_module.cc b/webrtc/modules/audio_coding/acm2/audio_coding_module.cc
index c4dd349cc4ddb3eeebf992a3456d8e93a647fcb7..a7e751f943c3c8c981695a8ebeff42776bc5ccb7 100644
--- a/webrtc/modules/audio_coding/acm2/audio_coding_module.cc
+++ b/webrtc/modules/audio_coding/acm2/audio_coding_module.cc
@@ -14,6 +14,7 @@
 #include "webrtc/common_types.h"
 #include "webrtc/modules/audio_coding/acm2/audio_coding_module_impl.h"
 #include "webrtc/modules/audio_coding/acm2/rent_a_codec.h"
+#include "webrtc/modules/audio_coding/codecs/builtin_audio_decoder_factory.h"
 #include "webrtc/system_wrappers/include/clock.h"
 #include "webrtc/system_wrappers/include/trace.h"
 
@@ -24,6 +25,7 @@ AudioCodingModule* AudioCodingModule::Create(int id) {
   Config config;
   config.id = id;
   config.clock = Clock::GetRealTimeClock();
+  config.decoder_factory = CreateBuiltinAudioDecoderFactory();

[the sun, 2016/05/03 21:07:30]

That's what I was thinking - until the legacy VoE API is deprecated, can we
avoid touching that and instantiate the built-in decoder factory here. For the
use case with AudioReceiveStream, we'd instead need a function on voe::Channel
(and ACM) to set the decoder factory, or possibly recreate the voe::Channel's
ACM.

   return Create(config);
 }
 
@@ -31,6 +33,7 @@ AudioCodingModule* AudioCodingModule::Create(int id, Clock* clock) {
   Config config;
   config.id = id;
   config.clock = clock;
+  config.decoder_factory = CreateBuiltinAudioDecoderFactory();
   return Create(config);
 }