Clean up the NetEqFactory API.

This CL decouples NetEqFactory and AudioDecoderFactory.
AudioDecoderFactory is used in more places than just inside of NetEq, so
decoupling these makes sense.

Bug: webrtc:11005
Change-Id: I78dd856e4248e398e69a65816b062ef30555b055
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/161005
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29961}

modules/audio_coding/neteq/tools/neteq_test.cc

@@ -13,8 +13,7 @@
 #include <iomanip>
 #include <iostream>
 
-#include "api/neteq/custom_neteq_factory.h"
-#include "api/neteq/default_neteq_controller_factory.h"
+#include "modules/audio_coding/neteq/default_neteq_factory.h"
 #include "modules/rtp_rtcp/source/byte_io.h"
 #include "system_wrappers/include/clock.h"
 
@@ -43,9 +42,7 @@ std::unique_ptr<NetEq> CreateNetEq(
     const NetEq::Config& config,
     Clock* clock,
     const rtc::scoped_refptr<AudioDecoderFactory>& decoder_factory) {
-  CustomNetEqFactory neteq_factory(
-      decoder_factory, std::make_unique<DefaultNetEqControllerFactory>());
-  return neteq_factory.CreateNetEq(config, clock);
+  return DefaultNetEqFactory().CreateNetEq(config, decoder_factory, clock);
 }
 
 }  // namespace