Reland "Remove CodecInst pt.1"

This is a reland of 056f9738bf7a3d16da45398239656e165c4e0851

Original change's description:
> Remove CodecInst pt.1
> 
> Update audio_coding tests to not use CodecInst.
> 
> Bug: webrtc:7626
> Change-Id: I880fb8d72d7d0a915d274e67feb6106f023697c2
> Reviewed-on: https://webrtc-review.googlesource.com/c/112594
> Commit-Queue: Fredrik Solenberg <solenberg@webrtc.org>
> Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
> Cr-Commit-Position: refs/heads/master@{#25879}

Bug: webrtc:7626
Change-Id: I5d6ca0baf6230bfe9bf95c2c25496d2a56812d90
Reviewed-on: https://webrtc-review.googlesource.com/c/112942
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Fredrik Solenberg <solenberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25902}
diff --git a/modules/audio_coding/test/opus_test.cc b/modules/audio_coding/test/opus_test.cc
index 954b183..1e24e5d 100644
--- a/modules/audio_coding/test/opus_test.cc
+++ b/modules/audio_coding/test/opus_test.cc
@@ -13,12 +13,9 @@
 #include <string>
 
 #include "api/audio_codecs/builtin_audio_decoder_factory.h"
-#include "common_types.h"  // NOLINT(build/include)
-#include "modules/audio_coding/codecs/audio_format_conversion.h"
 #include "modules/audio_coding/codecs/opus/opus_interface.h"
 #include "modules/audio_coding/include/audio_coding_module_typedefs.h"
 #include "modules/audio_coding/test/TestStereo.h"
-#include "modules/audio_coding/test/utility.h"
 #include "test/gtest.h"
 #include "test/testsupport/fileutils.h"
 
@@ -89,13 +86,10 @@
   EXPECT_EQ(0, acm_receiver_->InitializeReceiver());
 
   // Register Opus stereo as receiving codec.
-  CodecInst opus_codec_param;
-  int codec_id = acm_receiver_->Codec("opus", 48000, 2);
-  EXPECT_EQ(0, acm_receiver_->Codec(codec_id, &opus_codec_param));
-  payload_type_ = opus_codec_param.pltype;
-  EXPECT_EQ(true,
-            acm_receiver_->RegisterReceiveCodec(
-                opus_codec_param.pltype, CodecInstToSdp(opus_codec_param)));
+  constexpr int kOpusPayloadType = 120;
+  const SdpAudioFormat kOpusFormatStereo("opus", 48000, 2, {{"stereo", "1"}});
+  payload_type_ = kOpusPayloadType;
+  acm_receiver_->SetReceiveCodecs({{kOpusPayloadType, kOpusFormatStereo}});
 
   // Create and connect the channel.
   channel_a2b_ = new TestPackStereo;
@@ -159,10 +153,8 @@
   OpenOutFile(test_cntr);
 
   // Register Opus mono as receiving codec.
-  opus_codec_param.channels = 1;
-  EXPECT_EQ(true,
-            acm_receiver_->RegisterReceiveCodec(
-                opus_codec_param.pltype, CodecInstToSdp(opus_codec_param)));
+  const SdpAudioFormat kOpusFormatMono("opus", 48000, 2);
+  acm_receiver_->SetReceiveCodecs({{kOpusPayloadType, kOpusFormatMono}});
 
   // Run Opus with 2.5 ms frame size.
   Run(channel_a2b_, audio_channels, 32000, 120);