Revert of Reland Replace AudioFifo with a deque of AudioBus in ATR::AudioEncoder

content/renderer/media_recorder/audio_track_recorder.cc

Index: content/renderer/media_recorder/audio_track_recorder.cc
diff --git a/content/renderer/media_recorder/audio_track_recorder.cc b/content/renderer/media_recorder/audio_track_recorder.cc
index 9c017226e3a4361ca7244e5222f869ba3d9c428e..9f96801895a91ce1f8daa61b0ec50e1f6c6855b0 100644
--- a/content/renderer/media_recorder/audio_track_recorder.cc
+++ b/content/renderer/media_recorder/audio_track_recorder.cc
@@ -13,6 +13,7 @@
 #include "content/renderer/media/media_stream_audio_track.h"
 #include "media/base/audio_bus.h"
 #include "media/base/audio_converter.h"
+#include "media/base/audio_fifo.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/audio_sample_types.h"
 #include "media/base/bind_to_current_loop.h"
@@ -126,15 +127,13 @@
 
   // Sampling rate adapter between an OpusEncoder supported and the provided.
   std::unique_ptr<media::AudioConverter> converter_;
-  std::deque<std::unique_ptr<media::AudioBus>> audio_bus_queue_;
+  std::unique_ptr<media::AudioFifo> fifo_;
 
   // Buffer for passing AudioBus data to OpusEncoder.
   std::unique_ptr<float[]> buffer_;
 
   // While |paused_|, AudioBuses are not encoded.
   bool paused_;
-
-  int frames_queued_;
 
   OpusEncoder* opus_encoder_;
 
@@ -147,7 +146,6 @@
     : on_encoded_audio_cb_(on_encoded_audio_cb),
       bits_per_second_(bits_per_second),
       paused_(false),
-      frames_queued_(0),
       opus_encoder_(nullptr) {
   // AudioEncoder is constructed on the thread that ATR lives on, but should
   // operate only on the encoder thread after that. Reset
@@ -175,7 +173,6 @@
     DLOG(ERROR) << "Invalid params: " << input_params.AsHumanReadableString();
     return;
   }
-
   input_params_ = input_params;
   input_params_.set_frames_per_buffer(input_params_.sample_rate() *
                                       kOpusPreferredBufferDurationMs /
@@ -197,8 +194,9 @@
   converter_->AddInput(this);
   converter_->PrimeWithSilence();
 
-  frames_queued_ = 0;
-  audio_bus_queue_.clear();
+  fifo_.reset(new media::AudioFifo(
+      input_params_.channels(),
+      kMaxNumberOfFifoBuffers * input_params_.frames_per_buffer()));
 
   buffer_.reset(new float[output_params_.channels() *
                           output_params_.frames_per_buffer()]);
@@ -239,19 +237,14 @@
 
   if (!is_initialized() || paused_)
     return;
-
-  frames_queued_ += input_bus->frames();
-  audio_bus_queue_.push_back(std::move(input_bus));
-
-  const int max_frame_limit =
-      kMaxNumberOfFifoBuffers * input_params_.frames_per_buffer();
-  while (frames_queued_ > max_frame_limit) {
-    frames_queued_ -= audio_bus_queue_.front()->frames();
-    audio_bus_queue_.pop_front();
-  }
+  // TODO(mcasas): Consider using a std::deque<std::unique_ptr<AudioBus>>
+  // instead of
+  // an AudioFifo, to avoid copying data needlessly since we know the sizes of
+  // both input and output and they are multiples.
+  fifo_->Push(input_bus.get());
 
   // Wait to have enough |input_bus|s to guarantee a satisfactory conversion.
-  while (frames_queued_ >= input_params_.frames_per_buffer()) {
+  while (fifo_->frames() >= input_params_.frames_per_buffer()) {
     std::unique_ptr<media::AudioBus> audio_bus = media::AudioBus::Create(
         output_params_.channels(), kOpusPreferredFramesPerBuffer);
     converter_->Convert(audio_bus.get());
@@ -263,7 +256,7 @@
                  encoded_data.get())) {
       const base::TimeTicks capture_time_of_first_sample =
           capture_time -
-          base::TimeDelta::FromMicroseconds(frames_queued_ *
+          base::TimeDelta::FromMicroseconds(fifo_->frames() *
                                             base::Time::kMicrosecondsPerSecond /
                                             input_params_.sample_rate());
       on_encoded_audio_cb_.Run(output_params_, std::move(encoded_data),
@@ -275,14 +268,7 @@
 double AudioTrackRecorder::AudioEncoder::ProvideInput(
     media::AudioBus* audio_bus,
     uint32_t frames_delayed) {
-  if (audio_bus_queue_.empty()) {
-    audio_bus->Zero();
-    return 0.0;
-  }
-
-  frames_queued_ -= audio_bus->frames();
-  audio_bus_queue_.front()->CopyTo(audio_bus);
-  audio_bus_queue_.pop_front();
+  fifo_->Consume(audio_bus, 0, audio_bus->frames());
   return 1.0;  // Return volume greater than zero to indicate we have more data.
 }