Regression test for issue where Opus DTX status was being forgotten.

webrtc/modules/audio_coding/acm2/audio_coding_module.cc

 /*
  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 30 matching lines @@
 
   // Can be called multiple times for Codec, CNG, RED.
   int RegisterSendCodec(const CodecInst& send_codec) override;
 
   void RegisterExternalSendCodec(
       AudioEncoder* external_speech_encoder) override;
 
   void ModifyEncoder(
       FunctionView<void(std::unique_ptr<AudioEncoder>*)> modifier) override;
 
+  void QueryEncoder(FunctionView<void(const AudioEncoder*)> query) override;
+
   // Get current send codec.
   rtc::Optional<CodecInst> SendCodec() const override;
 
   // Get current send frequency.
   int SendFrequency() const override;
 
   // Sets the bitrate to the specified value in bits/sec. In case the codec does
   // not support the requested value it will choose an appropriate value
   // instead.
   void SetBitRate(int bitrate_bps) override;
@@ skipping 528 matching lines @@
   // Wipe the encoder factory, so that everything that relies on it will fail.
   // We don't want the complexity of supporting swapping back and forth.
   if (encoder_factory_) {
     encoder_factory_.reset();
     RTC_CHECK(!encoder_stack_);  // Ensure we hadn't started using the factory.
   }
 
   modifier(&encoder_stack_);
 }
 
+void AudioCodingModuleImpl::QueryEncoder(
+    FunctionView<void(const AudioEncoder*)> query) {
+  rtc::CritScope lock(&acm_crit_sect_);
+  query(encoder_stack_.get());
+}
+
 // Get current send codec.
 rtc::Optional<CodecInst> AudioCodingModuleImpl::SendCodec() const {
   rtc::CritScope lock(&acm_crit_sect_);
   if (encoder_factory_) {
     auto* ci = encoder_factory_->codec_manager.GetCodecInst();
     if (ci) {
       return rtc::Optional<CodecInst>(*ci);
     }
     CreateSpeechEncoderIfNecessary(encoder_factory_.get());
     const std::unique_ptr<AudioEncoder>& enc =
@@ skipping 724 matching lines @@
 // Checks the validity of the parameters of the given codec
 bool AudioCodingModule::IsCodecValid(const CodecInst& codec) {
   bool valid = acm2::RentACodec::IsCodecValid(codec);
   if (!valid)
     WEBRTC_TRACE(webrtc::kTraceError, webrtc::kTraceAudioCoding, -1,
                  "Invalid codec setting");
   return valid;
 }
 
 }  // namespace webrtc