Pass ownership of external encoders to the ACM

webrtc/modules/audio_coding/acm2/codec_manager.cc

 /*
  *  Copyright (c) 2015 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 95 matching lines @@
     case RentACodec::RegistrationResult::kSkip:
       break;
   }
 
   if (IsOpus(send_codec)) {
     // VAD/DTX not supported.
     codec_stack_params_.use_cng = false;
   }
 
   send_codec_inst_ = rtc::Optional<CodecInst>(send_codec);
-  codec_stack_params_.speech_encoder = nullptr;  // Caller must recreate it.
+  codec_stack_params_.speech_encoder.reset();  // Caller must recreate it.
   return true;
 }
 
 CodecInst CodecManager::ForgeCodecInst(
     const AudioEncoder* external_speech_encoder) {
   CodecInst ci;
   ci.channels = external_speech_encoder->NumChannels();
   ci.plfreq = external_speech_encoder->SampleRateHz();
   ci.pacsize = rtc::CheckedDivExact(
       static_cast<int>(external_speech_encoder->Max10MsFramesInAPacket() *
@@ skipping 58 matching lines @@
                  "Codec internal FEC and RED cannot be co-enabled.");
     return false;
   }
 
   codec_stack_params_.use_codec_fec = enable_codec_fec;
   return true;
 }
 
 }  // namespace acm2
 }  // namespace webrtc