Revert of Conversational speech tool, simualtor + unit tests (patchset #12 id:220001 of https://codereview.webrtc.org/2790933002/ )

Reason for revert:
Compile Error.

Original issue's description:
> The simulator puts into action the schedule of speech turns encoded in a MultiEndCall instance. The output is a set of audio track pairs. There is one set for each speaker and each set contains one near-end and one far-end audio track. The tracks are directly written into wav files instead of creating them in memory. To speed up the creation of the output wav files, *all* the source audio tracks (i.e., the atomic speech turns) are pre-loaded.
>
> The ConversationalSpeechTest.MultiEndCallSimulator unit test defines a conversational speech sequence and creates two wav files (with pure tones at 440 and 880 Hz) that are used as atomic speech turn tracks.
>
> This CL also patches MultiEndCall in order to allow input audio tracks with same sample rate and single channel only.
>
> BUG=webrtc:7218
>
> Review-Url: https://codereview.webrtc.org/2790933002
> Cr-Commit-Position: refs/heads/master@{#18480}
> Committed: https://chromium.googlesource.com/external/webrtc/+/6b648c4697cede14605fd2b89425866eec5f7c79

TBR=minyue@webrtc.org,alessiob@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=webrtc:7218

Review-Url: https://codereview.webrtc.org/2925123003
Cr-Commit-Position: refs/heads/master@{#18481}
diff --git a/webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn b/webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn
index af24f8a..b74c05b 100644
--- a/webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn
+++ b/webrtc/modules/audio_processing/test/conversational_speech/BUILD.gn
@@ -35,8 +35,6 @@
     "config.h",
     "multiend_call.cc",
     "multiend_call.h",
-    "simulator.cc",
-    "simulator.h",
     "timing.cc",
     "timing.h",
     "wavreader_abstract_factory.h",
@@ -69,8 +67,5 @@
     "../../../../../webrtc/test:test_support",
     "//testing/gmock",
     "//testing/gtest",
-    "//webrtc:webrtc_common",
-    "//webrtc/base:rtc_base_approved",
-    "//webrtc/test:test_support",
   ]
 }
diff --git a/webrtc/modules/audio_processing/test/conversational_speech/generator_unittest.cc b/webrtc/modules/audio_processing/test/conversational_speech/generator_unittest.cc
index 02513c4..6797beb 100644
--- a/webrtc/modules/audio_processing/test/conversational_speech/generator_unittest.cc
+++ b/webrtc/modules/audio_processing/test/conversational_speech/generator_unittest.cc
@@ -40,16 +40,13 @@
 #include <cmath>
 #include <map>
 #include <memory>
-#include <vector>
 
 #include "webrtc/base/logging.h"
-#include "webrtc/base/optional.h"
 #include "webrtc/base/pathutils.h"
 #include "webrtc/common_audio/wav_file.h"
 #include "webrtc/modules/audio_processing/test/conversational_speech/config.h"
 #include "webrtc/modules/audio_processing/test/conversational_speech/mock_wavreader_factory.h"
 #include "webrtc/modules/audio_processing/test/conversational_speech/multiend_call.h"
-#include "webrtc/modules/audio_processing/test/conversational_speech/simulator.h"
 #include "webrtc/modules/audio_processing/test/conversational_speech/timing.h"
 #include "webrtc/modules/audio_processing/test/conversational_speech/wavreader_factory.h"
 #include "webrtc/test/gmock.h"
@@ -86,12 +83,9 @@
 constexpr int kDefaultSampleRate = 48000;
 const std::map<std::string, const MockWavReaderFactory::Params>
     kDefaultMockWavReaderFactoryParamsMap = {
-  {"t300", {kDefaultSampleRate, 1u, 14400u}},  // Mono, 0.3 seconds.
-  {"t500", {kDefaultSampleRate, 1u, 24000u}},  // Mono, 0.5 seconds.
-  {"t1000", {kDefaultSampleRate, 1u, 48000u}},  // Mono, 1.0 seconds.
-  {"sr8000", {8000, 1u, 8000u}},  // 8kHz sample rate, mono, 1 second.
-  {"sr16000", {16000, 1u, 16000u}},  // 16kHz sample rate, mono, 1 second.
-  {"sr16000_stereo", {16000, 2u, 16000u}},  // Like sr16000, but stereo.
+  {"t300", {kDefaultSampleRate, 1u, 14400u}},  // 0.3 seconds.
+  {"t500", {kDefaultSampleRate, 1u, 24000u}},  // 0.5 seconds.
+  {"t1000", {kDefaultSampleRate, 1u, 48000u}},  // 1.0 seconds.
 };
 const MockWavReaderFactory::Params& kDefaultMockWavReaderFactoryParams =
     kDefaultMockWavReaderFactoryParamsMap.at("t500");
@@ -119,57 +113,6 @@
   wav_writer.WriteSamples(samples.data(), params.num_samples);
 }
 
-// Parameters to generate audio tracks with CreateSineWavFile.
-struct SineAudioTrackParams {
-  MockWavReaderFactory::Params params;
-  float frequency;
-};
-
-// Creates a temporary directory in which sine audio tracks are written.
-std::string CreateTemporarySineAudioTracks(
-    const std::map<std::string, SineAudioTrackParams>& sine_tracks_params) {
-  // Create temporary directory.
-  rtc::Pathname temp_directory(OutputPath());
-  temp_directory.AppendFolder("TempConversationalSpeechAudioTracks");
-  CreateDir(temp_directory.pathname());
-
-  // Create sine tracks.
-  for (const auto& it : sine_tracks_params) {
-    const rtc::Pathname temp_filepath(temp_directory.pathname(), it.first);
-    CreateSineWavFile(
-        temp_filepath.pathname(), it.second.params, it.second.frequency);
-  }
-
-  return temp_directory.pathname();
-}
-
-void CheckAudioTrackParams(const WavReaderFactory& wav_reader_factory,
-                           const std::string& filepath,
-                           const MockWavReaderFactory::Params& expeted_params) {
-  auto wav_reader = wav_reader_factory.Create(filepath);
-  EXPECT_EQ(expeted_params.sample_rate, wav_reader->SampleRate());
-  EXPECT_EQ(expeted_params.num_channels, wav_reader->NumChannels());
-  EXPECT_EQ(expeted_params.num_samples, wav_reader->NumSamples());
-}
-
-void DeleteFolderAndContents(const std::string& dir) {
-  if (!DirExists(dir)) { return; }
-  rtc::Optional<std::vector<std::string>> dir_content = ReadDirectory(dir);
-  EXPECT_TRUE(dir_content);
-  for (const auto& path : *dir_content) {
-    if (DirExists(path)) {
-      DeleteFolderAndContents(path);
-    } else if (FileExists(path)) {
-      // TODO(alessiob): Wrap with EXPECT_TRUE() once webrtc:7769 bug fixed.
-      RemoveFile(path);
-    } else {
-      FAIL();
-    }
-  }
-  // TODO(alessiob): Wrap with EXPECT_TRUE() once webrtc:7769 bug fixed.
-  RemoveDir(dir);
-}
-
 }  // namespace
 
 using testing::_;
@@ -195,8 +138,8 @@
 
 TEST_F(ConversationalSpeechTest, TimingSaveLoad) {
   // Save test timing.
-  const std::string temporary_filepath = TempFilename(
-      OutputPath(), "TempTimingTestFile");
+  const std::string temporary_filepath = webrtc::test::TempFilename(
+      webrtc::test::OutputPath(), "TempTimingTestFile");
   SaveTiming(temporary_filepath, expected_timing);
 
   // Create a std::vector<Turn> instance by loading from file.
@@ -230,52 +173,6 @@
   EXPECT_EQ(6u, multiend_call.speaking_turns().size());
 }
 
-TEST_F(ConversationalSpeechTest, MultiEndCallSetupDifferentSampleRates) {
-  const std::vector<Turn> timing = {
-      {"A", "sr8000", 0},
-      {"B", "sr16000", 0},
-  };
-  auto mock_wavreader_factory = CreateMockWavReaderFactory();
-
-  // There are two unique audio tracks to read.
-  EXPECT_CALL(*mock_wavreader_factory, Create(testing::_)).Times(2);
-
-  MultiEndCall multiend_call(
-      timing, audiotracks_path, std::move(mock_wavreader_factory));
-  EXPECT_FALSE(multiend_call.valid());
-}
-
-TEST_F(ConversationalSpeechTest, MultiEndCallSetupMultipleChannels) {
-  const std::vector<Turn> timing = {
-      {"A", "sr16000_stereo", 0},
-      {"B", "sr16000_stereo", 0},
-  };
-  auto mock_wavreader_factory = CreateMockWavReaderFactory();
-
-  // There is one unique audio track to read.
-  EXPECT_CALL(*mock_wavreader_factory, Create(testing::_)).Times(1);
-
-  MultiEndCall multiend_call(
-      timing, audiotracks_path, std::move(mock_wavreader_factory));
-  EXPECT_FALSE(multiend_call.valid());
-}
-
-TEST_F(ConversationalSpeechTest,
-       MultiEndCallSetupDifferentSampleRatesAndMultipleNumChannels) {
-  const std::vector<Turn> timing = {
-      {"A", "sr8000", 0},
-      {"B", "sr16000_stereo", 0},
-  };
-  auto mock_wavreader_factory = CreateMockWavReaderFactory();
-
-  // There are two unique audio tracks to read.
-  EXPECT_CALL(*mock_wavreader_factory, Create(testing::_)).Times(2);
-
-  MultiEndCall multiend_call(
-      timing, audiotracks_path, std::move(mock_wavreader_factory));
-  EXPECT_FALSE(multiend_call.valid());
-}
-
 TEST_F(ConversationalSpeechTest, MultiEndCallSetupFirstOffsetNegative) {
   const std::vector<Turn> timing = {
       {"A", "t500", -100},
@@ -628,70 +525,20 @@
     const std::size_t num_samples = duration_seconds * sample_rate;
     MockWavReaderFactory::Params params = {sample_rate, 1u, num_samples};
     CreateSineWavFile(temp_filename.pathname(), params);
+    LOG(LS_VERBOSE) << "wav file @" << sample_rate << " Hz created ("
+        << num_samples << " samples)";
 
     // Load wav file and check if params match.
     WavReaderFactory wav_reader_factory;
-    MockWavReaderFactory::Params expeted_params = {
-        sample_rate, 1u, num_samples};
-    CheckAudioTrackParams(
-        wav_reader_factory, temp_filename.pathname(), expeted_params);
+    auto wav_reader = wav_reader_factory.Create(temp_filename.pathname());
+    EXPECT_EQ(sample_rate, wav_reader->SampleRate());
+    EXPECT_EQ(1u, wav_reader->NumChannels());
+    EXPECT_EQ(num_samples, wav_reader->NumSamples());
 
     // Clean up.
     remove(temp_filename.pathname().c_str());
   }
 }
 
-TEST_F(ConversationalSpeechTest, MultiEndCallSimulator) {
-  // Simulated call (one character corresponding to 500 ms):
-  // A 0*********...........2*********.....
-  // B ...........1*********.....3*********
-  const std::vector<Turn> expected_timing = {
-      {"A", "t5000_440.wav", 0},
-      {"B", "t5000_880.wav", 500},
-      {"A", "t5000_440.wav", 0},
-      {"B", "t5000_880.wav", -2500},
-  };
-  const std::size_t expected_duration_seconds = 18;
-
-  // Create temporary audio track files.
-  const int sample_rate = 16000;
-  const std::map<std::string, SineAudioTrackParams> sine_tracks_params = {
-      {"t5000_440.wav", {{sample_rate, 1u, sample_rate * 5}, 440.0}},
-      {"t5000_880.wav", {{sample_rate, 1u, sample_rate * 5}, 880.0}},
-  };
-  const std::string audiotracks_path = CreateTemporarySineAudioTracks(
-      sine_tracks_params);
-
-  // Set up the multi-end call.
-  auto wavreader_factory = std::unique_ptr<WavReaderFactory>(
-      new WavReaderFactory());
-  MultiEndCall multiend_call(
-      expected_timing, audiotracks_path, std::move(wavreader_factory));
-
-  // Simulate the call.
-  rtc::Pathname output_path(audiotracks_path);
-  output_path.AppendFolder("output");
-  CreateDir(output_path.pathname());
-  LOG(LS_VERBOSE) << "simulator output path: " << output_path.pathname();
-  auto generated_audiotrak_pairs = conversational_speech::Simulate(
-      multiend_call, output_path.pathname());
-  EXPECT_EQ(2u, generated_audiotrak_pairs->size());
-
-  // Check the output.
-  WavReaderFactory wav_reader_factory;
-  const MockWavReaderFactory::Params expeted_params = {
-      sample_rate, 1u, sample_rate * expected_duration_seconds};
-  for (const auto& it : *generated_audiotrak_pairs) {
-    LOG(LS_VERBOSE) << "checking far/near-end for <" << it.first << ">";
-    CheckAudioTrackParams(
-        wav_reader_factory, it.second.near_end, expeted_params);
-    CheckAudioTrackParams(
-        wav_reader_factory, it.second.far_end, expeted_params);
-  }
-
-  // Clean.
-  EXPECT_NO_FATAL_FAILURE(DeleteFolderAndContents(audiotracks_path));
-}
-
 }  // namespace test
 }  // namespace webrtc
diff --git a/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc b/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc
index f83923c..624f981 100644
--- a/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc
+++ b/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.cc
@@ -24,15 +24,36 @@
     rtc::ArrayView<const Turn> timing, const std::string& audiotracks_path,
     std::unique_ptr<WavReaderAbstractFactory> wavreader_abstract_factory)
         : timing_(timing), audiotracks_path_(audiotracks_path),
-          wavreader_abstract_factory_(std::move(wavreader_abstract_factory)),
-          valid_(false) {
+          wavreader_abstract_factory_(std::move(wavreader_abstract_factory)) {
   FindSpeakerNames();
-  if (CreateAudioTrackReaders())
-    valid_ = CheckTiming();
+  CreateAudioTrackReaders();
+  valid_ = CheckTiming();
 }
 
 MultiEndCall::~MultiEndCall() = default;
 
+const std::set<std::string>& MultiEndCall::speaker_names() const {
+  return speaker_names_;
+}
+
+const std::map<std::string, std::unique_ptr<WavReaderInterface>>&
+    MultiEndCall::audiotrack_readers() const {
+  return audiotrack_readers_;
+}
+
+bool MultiEndCall::valid() const {
+  return valid_;
+}
+
+size_t MultiEndCall::total_duration_samples() const {
+  return total_duration_samples_;
+}
+
+const std::vector<MultiEndCall::SpeakingTurn>& MultiEndCall::speaking_turns()
+    const {
+  return speaking_turns_;
+}
+
 void MultiEndCall::FindSpeakerNames() {
   RTC_DCHECK(speaker_names_.empty());
   for (const Turn& turn : timing_) {
@@ -40,9 +61,8 @@
   }
 }
 
-bool MultiEndCall::CreateAudioTrackReaders() {
+void MultiEndCall::CreateAudioTrackReaders() {
   RTC_DCHECK(audiotrack_readers_.empty());
-  sample_rate_hz_ = 0;  // Sample rate will be set when reading the first track.
   for (const Turn& turn : timing_) {
     auto it = audiotrack_readers_.find(turn.audiotrack_file_name);
     if (it != audiotrack_readers_.end())
@@ -55,24 +75,9 @@
     // Map the audiotrack file name to a new instance of WavReaderInterface.
     std::unique_ptr<WavReaderInterface> wavreader =
         wavreader_abstract_factory_->Create(audiotrack_file_path.pathname());
-
-    if (sample_rate_hz_ == 0) {
-      sample_rate_hz_ = wavreader->SampleRate();
-    } else if (sample_rate_hz_ != wavreader->SampleRate()) {
-      LOG(LS_ERROR) << "All the audio tracks should have the same sample rate.";
-      return false;
-    }
-
-    if (wavreader->NumChannels() != 1) {
-      LOG(LS_ERROR) << "Only mono audio tracks supported.";
-      return false;
-    }
-
     audiotrack_readers_.emplace(
         turn.audiotrack_file_name, std::move(wavreader));
   }
-
-  return true;
 }
 
 bool MultiEndCall::CheckTiming() {
diff --git a/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.h b/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.h
index 1daeea0..dd03a07 100644
--- a/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.h
+++ b/webrtc/modules/audio_processing/test/conversational_speech/multiend_call.h
@@ -50,23 +50,19 @@
       std::unique_ptr<WavReaderAbstractFactory> wavreader_abstract_factory);
   ~MultiEndCall();
 
-  const std::set<std::string>& speaker_names() const { return speaker_names_; }
+  const std::set<std::string>& speaker_names() const;
   const std::map<std::string, std::unique_ptr<WavReaderInterface>>&
-      audiotrack_readers() const { return audiotrack_readers_; }
-  bool valid() const { return valid_; }
-  int sample_rate() const { return sample_rate_hz_; }
-  size_t total_duration_samples() const { return total_duration_samples_; }
-  const std::vector<SpeakingTurn>& speaking_turns() const {
-      return speaking_turns_; }
+      audiotrack_readers() const;
+  bool valid() const;
+  size_t total_duration_samples() const;
+  const std::vector<SpeakingTurn>& speaking_turns() const;
 
  private:
   // Finds unique speaker names.
   void FindSpeakerNames();
 
-  // Creates one WavReader instance for each unique audiotrack. It returns false
-  // if the audio tracks do not have the same sample rate or if they are not
-  // mono.
-  bool CreateAudioTrackReaders();
+  // Creates one WavReader instance for each unique audiotrack.
+  void CreateAudioTrackReaders();
 
   // Validates the speaking turns timing information. Accepts cross-talk, but
   // only up to 2 speakers. Rejects unordered turns and self cross-talk.
@@ -79,7 +75,6 @@
   std::map<std::string, std::unique_ptr<WavReaderInterface>>
       audiotrack_readers_;
   bool valid_;
-  int sample_rate_hz_;
   size_t total_duration_samples_;
   std::vector<SpeakingTurn> speaking_turns_;
 
diff --git a/webrtc/modules/audio_processing/test/conversational_speech/simulator.cc b/webrtc/modules/audio_processing/test/conversational_speech/simulator.cc
deleted file mode 100644
index 705b1df..0000000
--- a/webrtc/modules/audio_processing/test/conversational_speech/simulator.cc
+++ /dev/null
@@ -1,221 +0,0 @@
-/*
- *  Copyright (c) 2017 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.
- */
-
-#include "webrtc/modules/audio_processing/test/conversational_speech/simulator.h"
-
-#include <set>
-#include <utility>
-#include <vector>
-
-#include "webrtc/base/array_view.h"
-#include "webrtc/base/constructormagic.h"
-#include "webrtc/base/logging.h"
-#include "webrtc/base/pathutils.h"
-#include "webrtc/base/ptr_util.h"
-#include "webrtc/common_audio/wav_file.h"
-#include "webrtc/modules/audio_processing/test/conversational_speech/wavreader_interface.h"
-
-namespace webrtc {
-namespace test {
-namespace {
-
-using conversational_speech::MultiEndCall;
-using conversational_speech::SpeakerOutputFilePaths;
-using conversational_speech::WavReaderInterface;
-
-// Combines output path and speaker names to define the output file paths for
-// the near-end and far=end audio tracks.
-std::unique_ptr<std::map<std::string, SpeakerOutputFilePaths>>
-    InitSpeakerOutputFilePaths(const std::set<std::string>& speaker_names,
-                               const std::string& output_path) {
-  // Create map.
-  auto speaker_output_file_paths_map = rtc::MakeUnique<
-      std::map<std::string, SpeakerOutputFilePaths>>();
-
-  // Add near-end and far-end output paths into the map.
-  for (const auto& speaker_name : speaker_names) {
-    const rtc::Pathname near_end_path(
-        output_path, "s_" + speaker_name + "-near_end.wav");
-    LOG(LS_VERBOSE) << "The near-end audio track will be created in "
-        << near_end_path.pathname() << ".";
-
-    const rtc::Pathname far_end_path(
-        output_path, "s_" + speaker_name + "-far_end.wav");
-    LOG(LS_VERBOSE) << "The far-end audio track will be created in "
-        << far_end_path.pathname() << ".";
-
-    // Add to map.
-    speaker_output_file_paths_map->emplace(
-        std::piecewise_construct,
-        std::forward_as_tuple(speaker_name),
-        std::forward_as_tuple(near_end_path.pathname(),
-                              far_end_path.pathname()));
-  }
-
-  return speaker_output_file_paths_map;
-}
-
-// Class that provides one WavWriter for the near-end and one for the far-end
-// output track of a speaker.
-class SpeakerWavWriters {
- public:
-  SpeakerWavWriters(
-      const SpeakerOutputFilePaths& output_file_paths, int sample_rate)
-          : near_end_wav_writer_(output_file_paths.near_end, sample_rate, 1u),
-            far_end_wav_writer_(output_file_paths.far_end, sample_rate, 1u) {}
-  WavWriter* near_end_wav_writer() {
-    return &near_end_wav_writer_;
-  }
-  WavWriter* far_end_wav_writer() {
-    return &far_end_wav_writer_;
-  }
- private:
-  WavWriter near_end_wav_writer_;
-  WavWriter far_end_wav_writer_;
-};
-
-// Initializes one WavWriter instance for each speaker and both the near-end and
-// far-end output tracks.
-std::unique_ptr<std::map<std::string, SpeakerWavWriters>>
-    InitSpeakersWavWriters(const std::map<std::string, SpeakerOutputFilePaths>&
-                           speaker_output_file_paths, int sample_rate) {
-  // Create map.
-  auto speaker_wav_writers_map = rtc::MakeUnique<
-      std::map<std::string, SpeakerWavWriters>>();
-
-  // Add SpeakerWavWriters instance into the map.
-  for (auto it = speaker_output_file_paths.begin();
-      it != speaker_output_file_paths.end(); ++it) {
-    speaker_wav_writers_map->emplace(
-        std::piecewise_construct,
-        std::forward_as_tuple(it->first),
-        std::forward_as_tuple(it->second, sample_rate));
-  }
-
-  return speaker_wav_writers_map;
-}
-
-// Reads all the samples for each audio track.
-std::unique_ptr<std::map<std::string, std::vector<int16_t>>> PreloadAudioTracks(
-    const std::map<std::string, std::unique_ptr<WavReaderInterface>>&
-        audiotrack_readers) {
-  // Create map.
-  auto audiotracks_map = rtc::MakeUnique<
-      std::map<std::string, std::vector<int16_t>>>();
-
-  // Add audio track vectors.
-  for (auto it = audiotrack_readers.begin(); it != audiotrack_readers.end();
-      ++it) {
-    // Add map entry.
-    audiotracks_map->emplace(
-        std::piecewise_construct,
-        std::forward_as_tuple(it->first),
-        std::forward_as_tuple(it->second->NumSamples()));
-
-    // Read samples.
-    it->second->ReadInt16Samples(audiotracks_map->at(it->first));
-  }
-
-  return audiotracks_map;
-}
-
-// Writes all the values in |source_samples| via |wav_writer|. If the number of
-// previously written samples in |wav_writer| is less than |interval_begin|, it
-// adds zeros as left padding. The padding corresponds to intervals during which
-// a speaker is not active.
-void PadLeftWriteChunk(rtc::ArrayView<const int16_t> source_samples,
-                       size_t interval_begin, WavWriter* wav_writer) {
-  // Add left padding.
-  RTC_CHECK(wav_writer);
-  RTC_CHECK_GE(interval_begin, wav_writer->num_samples());
-  size_t padding_size = interval_begin - wav_writer->num_samples();
-  if (padding_size != 0) {
-    const std::vector<int16_t> padding(padding_size, 0);
-    wav_writer->WriteSamples(padding.data(), padding_size);
-  }
-
-  // Write source samples.
-  wav_writer->WriteSamples(source_samples.data(), source_samples.size());
-}
-
-// Appends zeros via |wav_writer|. The number of zeros is always non-negative
-// and equal to the difference between the previously written samples and
-// |pad_samples|.
-void PadRightWrite(WavWriter* wav_writer, size_t pad_samples) {
-  RTC_CHECK(wav_writer);
-  RTC_CHECK_GE(pad_samples, wav_writer->num_samples());
-  size_t padding_size = pad_samples - wav_writer->num_samples();
-  if (padding_size != 0) {
-    const std::vector<int16_t> padding(padding_size, 0);
-    wav_writer->WriteSamples(padding.data(), padding_size);
-  }
-}
-
-}  // namespace
-
-namespace conversational_speech {
-
-std::unique_ptr<std::map<std::string, SpeakerOutputFilePaths>> Simulate(
-    const MultiEndCall& multiend_call, const std::string& output_path) {
-  // Set output file paths and initialize wav writers.
-  const auto& speaker_names = multiend_call.speaker_names();
-  auto speaker_output_file_paths = InitSpeakerOutputFilePaths(
-      speaker_names, output_path);
-  auto speakers_wav_writers = InitSpeakersWavWriters(
-      *speaker_output_file_paths, multiend_call.sample_rate());
-
-  // Preload all the input audio tracks.
-  const auto& audiotrack_readers = multiend_call.audiotrack_readers();
-  auto audiotracks = PreloadAudioTracks(audiotrack_readers);
-
-  // TODO(alessiob): When speaker_names.size() == 2, near-end and far-end
-  // across the 2 speakers are symmetric; hence, the code below could be
-  // replaced by only creating the near-end or the far-end. However, this would
-  // require to split the unit tests and document the behavior in README.md.
-  // In practice, it should not be an issue since the files are not expected to
-  // be signinificant.
-
-  // Write near-end and far-end output tracks.
-  for (const auto& speaking_turn : multiend_call.speaking_turns()) {
-    const std::string& active_speaker_name = speaking_turn.speaker_name;
-    auto source_audiotrack = audiotracks->at(
-        speaking_turn.audiotrack_file_name);
-
-    // Write active speaker's chunk to active speaker's near-end.
-    PadLeftWriteChunk(source_audiotrack, speaking_turn.begin,
-                      speakers_wav_writers->at(
-                          active_speaker_name).near_end_wav_writer());
-
-    // Write active speaker's chunk to other participants' far-ends.
-    for (const std::string& speaker_name : speaker_names) {
-      if (speaker_name == active_speaker_name)
-        continue;
-      PadLeftWriteChunk(source_audiotrack, speaking_turn.begin,
-                        speakers_wav_writers->at(
-                            speaker_name).far_end_wav_writer());
-    }
-  }
-
-  // Finalize all the output tracks with right padding.
-  // This is required to make all the output tracks duration equal.
-  size_t duration_samples = multiend_call.total_duration_samples();
-  for (const std::string& speaker_name : speaker_names) {
-    PadRightWrite(speakers_wav_writers->at(speaker_name).near_end_wav_writer(),
-                  duration_samples);
-    PadRightWrite(speakers_wav_writers->at(speaker_name).far_end_wav_writer(),
-                  duration_samples);
-  }
-
-  return speaker_output_file_paths;
-}
-
-}  // namespace conversational_speech
-}  // namespace test
-}  // namespace webrtc
diff --git a/webrtc/modules/audio_processing/test/conversational_speech/simulator.h b/webrtc/modules/audio_processing/test/conversational_speech/simulator.h
deleted file mode 100644
index 6224162..0000000
--- a/webrtc/modules/audio_processing/test/conversational_speech/simulator.h
+++ /dev/null
@@ -1,44 +0,0 @@
-/*
- *  Copyright (c) 2017 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.
- */
-
-#ifndef WEBRTC_MODULES_AUDIO_PROCESSING_TEST_CONVERSATIONAL_SPEECH_SIMULATOR_H_
-#define WEBRTC_MODULES_AUDIO_PROCESSING_TEST_CONVERSATIONAL_SPEECH_SIMULATOR_H_
-
-#include <map>
-#include <memory>
-#include <string>
-#include <utility>
-
-#include "webrtc/base/constructormagic.h"
-#include "webrtc/modules/audio_processing/test/conversational_speech/multiend_call.h"
-
-namespace webrtc {
-namespace test {
-namespace conversational_speech {
-
-struct SpeakerOutputFilePaths {
-  SpeakerOutputFilePaths(const std::string& new_near_end,
-                         const std::string& new_far_end)
-      : near_end(new_near_end),
-        far_end(new_far_end) {}
-  // Paths to the near-end and far-end audio track files.
-  const std::string near_end;
-  const std::string far_end;
-};
-
-// Generates the near-end and far-end audio track pairs for each speaker.
-std::unique_ptr<std::map<std::string, SpeakerOutputFilePaths>>
-    Simulate(const MultiEndCall& multiend_call, const std::string& output_path);
-
-}  // namespace conversational_speech
-}  // namespace test
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_TEST_CONVERSATIONAL_SPEECH_SIMULATOR_H_