Modernize variable names

As promised in
https://codereview.webrtc.org/1946873003/diff/1/webrtc/modules/utility/source/coder.h#newcode54

NOTRY=True

Review-Url: https://codereview.webrtc.org/1968853002
Cr-Commit-Position: refs/heads/master@{#12683}
diff --git a/webrtc/modules/utility/source/coder.cc b/webrtc/modules/utility/source/coder.cc
index a376cc7..9e43ca8 100644
--- a/webrtc/modules/utility/source/coder.cc
+++ b/webrtc/modules/utility/source/coder.cc
@@ -14,83 +14,83 @@
 
 namespace webrtc {
 
-AudioCoder::AudioCoder(uint32_t instanceID)
-    : _acm(AudioCodingModule::Create(instanceID)),
-      _receiveCodec(),
-      _encodeTimestamp(0),
-      _encodedData(NULL),
-      _encodedLengthInBytes(0),
-      _decodeTimestamp(0) {
-  _acm->InitializeReceiver();
-  _acm->RegisterTransportCallback(this);
+AudioCoder::AudioCoder(uint32_t instance_id)
+    : acm_(AudioCodingModule::Create(instance_id)),
+      receive_codec_(),
+      encode_timestamp_(0),
+      encoded_data_(nullptr),
+      encoded_length_in_bytes_(0),
+      decode_timestamp_(0) {
+  acm_->InitializeReceiver();
+  acm_->RegisterTransportCallback(this);
 }
 
 AudioCoder::~AudioCoder() {}
 
-int32_t AudioCoder::SetEncodeCodec(const CodecInst& codecInst) {
-  const bool success = codec_manager_.RegisterEncoder(codecInst) &&
-                       codec_manager_.MakeEncoder(&rent_a_codec_, _acm.get());
+int32_t AudioCoder::SetEncodeCodec(const CodecInst& codec_inst) {
+  const bool success = codec_manager_.RegisterEncoder(codec_inst) &&
+                       codec_manager_.MakeEncoder(&rent_a_codec_, acm_.get());
   return success ? 0 : -1;
 }
 
-int32_t AudioCoder::SetDecodeCodec(const CodecInst& codecInst) {
-  if (_acm->RegisterReceiveCodec(
-          codecInst, [&] { return rent_a_codec_.RentIsacDecoder(); }) == -1) {
+int32_t AudioCoder::SetDecodeCodec(const CodecInst& codec_inst) {
+  if (acm_->RegisterReceiveCodec(
+          codec_inst, [&] { return rent_a_codec_.RentIsacDecoder(); }) == -1) {
     return -1;
   }
-  memcpy(&_receiveCodec, &codecInst, sizeof(CodecInst));
+  memcpy(&receive_codec_, &codec_inst, sizeof(CodecInst));
   return 0;
 }
 
-int32_t AudioCoder::Decode(AudioFrame& decodedAudio,
-                           uint32_t sampFreqHz,
-                           const int8_t* incomingPayload,
-                           size_t payloadLength) {
-  if (payloadLength > 0) {
-    const uint8_t payloadType = _receiveCodec.pltype;
-    _decodeTimestamp += _receiveCodec.pacsize;
-    if (_acm->IncomingPayload((const uint8_t*)incomingPayload, payloadLength,
-                              payloadType, _decodeTimestamp) == -1) {
+int32_t AudioCoder::Decode(AudioFrame& decoded_audio,
+                           uint32_t samp_freq_hz,
+                           const int8_t* incoming_payload,
+                           size_t payload_length) {
+  if (payload_length > 0) {
+    const uint8_t payload_type = receive_codec_.pltype;
+    decode_timestamp_ += receive_codec_.pacsize;
+    if (acm_->IncomingPayload((const uint8_t*)incoming_payload, payload_length,
+                              payload_type, decode_timestamp_) == -1) {
       return -1;
     }
   }
-  return _acm->PlayoutData10Ms((uint16_t)sampFreqHz, &decodedAudio);
+  return acm_->PlayoutData10Ms((uint16_t)samp_freq_hz, &decoded_audio);
 }
 
-int32_t AudioCoder::PlayoutData(AudioFrame& decodedAudio,
-                                uint16_t& sampFreqHz) {
-  return _acm->PlayoutData10Ms(sampFreqHz, &decodedAudio);
+int32_t AudioCoder::PlayoutData(AudioFrame& decoded_audio,
+                                uint16_t& samp_freq_hz) {
+  return acm_->PlayoutData10Ms(samp_freq_hz, &decoded_audio);
 }
 
 int32_t AudioCoder::Encode(const AudioFrame& audio,
-                           int8_t* encodedData,
-                           size_t& encodedLengthInBytes) {
+                           int8_t* encoded_data,
+                           size_t& encoded_length_in_bytes) {
   // Fake a timestamp in case audio doesn't contain a correct timestamp.
   // Make a local copy of the audio frame since audio is const
-  AudioFrame audioFrame;
-  audioFrame.CopyFrom(audio);
-  audioFrame.timestamp_ = _encodeTimestamp;
-  _encodeTimestamp += static_cast<uint32_t>(audioFrame.samples_per_channel_);
+  AudioFrame audio_frame;
+  audio_frame.CopyFrom(audio);
+  audio_frame.timestamp_ = encode_timestamp_;
+  encode_timestamp_ += static_cast<uint32_t>(audio_frame.samples_per_channel_);
 
   // For any codec with a frame size that is longer than 10 ms the encoded
   // length in bytes should be zero until a a full frame has been encoded.
-  _encodedLengthInBytes = 0;
-  if (_acm->Add10MsData((AudioFrame&)audioFrame) == -1) {
+  encoded_length_in_bytes_ = 0;
+  if (acm_->Add10MsData((AudioFrame&)audio_frame) == -1) {
     return -1;
   }
-  _encodedData = encodedData;
-  encodedLengthInBytes = _encodedLengthInBytes;
+  encoded_data_ = encoded_data;
+  encoded_length_in_bytes = encoded_length_in_bytes_;
   return 0;
 }
 
-int32_t AudioCoder::SendData(FrameType /* frameType */,
-                             uint8_t /* payloadType */,
-                             uint32_t /* timeStamp */,
-                             const uint8_t* payloadData,
-                             size_t payloadSize,
+int32_t AudioCoder::SendData(FrameType /* frame_type */,
+                             uint8_t /* payload_type */,
+                             uint32_t /* time_stamp */,
+                             const uint8_t* payload_data,
+                             size_t payload_size,
                              const RTPFragmentationHeader* /* fragmentation*/) {
-  memcpy(_encodedData, payloadData, sizeof(uint8_t) * payloadSize);
-  _encodedLengthInBytes = payloadSize;
+  memcpy(encoded_data_, payload_data, sizeof(uint8_t) * payload_size);
+  encoded_length_in_bytes_ = payload_size;
   return 0;
 }