Revert of Implement the NackModule as part of the new jitter buffer. (patchset #19 id:360001 of https://codereview.webrtc.org/1715673002/ )

Reason for revert:
Unfortunately this breaks in the main waterfall: https://build.chromium.org/p/client.webrtc/builders/Android32%20Builder/builds/6362

I think it's related to dcheck_always_on=1 which is set in GYP_DEFINES only on the trybots, but not on the bots in the main waterfall.

Original issue's description:
> Implement the NackModule as part of the new jitter buffer.
>
> Things done/implemented in this CL:
>   - An interface that can send Nack (VCMNackSender).
>   - An interface that can request KeyFrames (VCMKeyFrameRequestSender).
>   - The nack module (NackModule).
>   - A set of convenience functions for modular numbers (mod_ops.h).
>
> BUG=webrtc:5514
>
> Committed: https://crrev.com/f472c5b6722dfb221f929fc4d3a2b4ca54647701
> Cr-Commit-Position: refs/heads/master@{#11882}

TBR=sprang@webrtc.org,stefan@webrtc.org,terelius@webrtc.org,torbjorng@webrtc.org,perkj@webrtc.org,tommi@webrtc.org,philipel@webrtc.org
BUG=webrtc:5514
NOTRY=True

Review URL: https://codereview.webrtc.org/1771883002

Cr-Commit-Position: refs/heads/master@{#11887}
diff --git a/webrtc/base/base.gyp b/webrtc/base/base.gyp
index 5ac173c..a6b2b1c 100644
--- a/webrtc/base/base.gyp
+++ b/webrtc/base/base.gyp
@@ -102,7 +102,6 @@
         'md5.h',
         'md5digest.cc',
         'md5digest.h',
-        'mod_ops.h',
         'optional.h',
         'platform_file.cc',
         'platform_file.h',
diff --git a/webrtc/base/base_tests.gyp b/webrtc/base/base_tests.gyp
index 2467b74..566ddeb 100644
--- a/webrtc/base/base_tests.gyp
+++ b/webrtc/base/base_tests.gyp
@@ -75,7 +75,6 @@
           'md5digest_unittest.cc',
           'messagedigest_unittest.cc',
           'messagequeue_unittest.cc',
-          'mod_ops_unittest.cc',
           'multipart_unittest.cc',
           'nat_unittest.cc',
           'network_unittest.cc',
diff --git a/webrtc/base/mod_ops.h b/webrtc/base/mod_ops.h
deleted file mode 100644
index 9e649b7..0000000
--- a/webrtc/base/mod_ops.h
+++ /dev/null
@@ -1,123 +0,0 @@
-/*
- *  Copyright (c) 2016 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_BASE_MOD_OPS_H_
-#define WEBRTC_BASE_MOD_OPS_H_
-
-#include <limits>
-#include <type_traits>
-
-#include "webrtc/base/checks.h"
-
-#define MOD_OPS_ASSERT_TYPE_IS_UNSIGNED(T)              \
-  static_assert(std::numeric_limits<T>::is_integer &&   \
-                    !std::numeric_limits<T>::is_signed, \
-                "Type must be of unsigned integer.")
-
-namespace webrtc {
-
-template <unsigned long M>                                    // NOLINT
-inline unsigned long Add(unsigned long a, unsigned long b) {  // NOLINT
-  RTC_DCHECK_LT(a, M);
-  unsigned long t = M - b % M;  // NOLINT
-  unsigned long res = a - t;    // NOLINT
-  if (t > a)
-    return res + M;
-  return res;
-}
-
-template <unsigned long M>                                         // NOLINT
-inline unsigned long Subtract(unsigned long a, unsigned long b) {  // NOLINT
-  RTC_DCHECK_LT(a, M);
-  unsigned long sub = b % M;  // NOLINT
-  if (a < sub)
-    return M - (sub - a);
-  return a - sub;
-}
-
-// Calculates the forward difference between two numbers.
-//
-// Example:
-// uint8_t x = 253;
-// uint8_t y = 2;
-//
-// ForwardDiff(x, y) == 4
-//
-//   252   253   254   255    0     1     2     3
-// #################################################
-// |     |  x  |     |     |     |     |  y  |     |
-// #################################################
-//          |----->----->----->----->----->
-//
-// ForwardDiff(y, x) == 251
-//
-//   252   253   254   255    0     1     2     3
-// #################################################
-// |     |  x  |     |     |     |     |  y  |     |
-// #################################################
-// -->----->                              |----->---
-//
-template <typename T>
-inline T ForwardDiff(T a, T b) {
-  MOD_OPS_ASSERT_TYPE_IS_UNSIGNED(T);
-  return b - a;
-}
-
-// Calculates the reverse difference between two numbers.
-//
-// Example:
-// uint8_t x = 253;
-// uint8_t y = 2;
-//
-// ReverseDiff(y, x) == 5
-//
-//   252   253   254   255    0     1     2     3
-// #################################################
-// |     |  x  |     |     |     |     |  y  |     |
-// #################################################
-//          <-----<-----<-----<-----<-----|
-//
-// ReverseDiff(x, y) == 251
-//
-//   252   253   254   255    0     1     2     3
-// #################################################
-// |     |  x  |     |     |     |     |  y  |     |
-// #################################################
-// ---<-----|                             |<-----<--
-//
-template <typename T>
-inline T ReverseDiff(T a, T b) {
-  MOD_OPS_ASSERT_TYPE_IS_UNSIGNED(T);
-  return a - b;
-}
-
-// Test if the sequence number a is ahead or at sequence number b.
-// If the two sequence numbers are at max distance from each other
-// then the sequence number with highest value is considered to
-// be ahead.
-template <typename T>
-inline bool AheadOrAt(T a, T b) {
-  MOD_OPS_ASSERT_TYPE_IS_UNSIGNED(T);
-  const T maxDist = std::numeric_limits<T>::max() / 2 + T(1);
-  if (a - b == maxDist)
-    return b < a;
-  return ForwardDiff(b, a) < maxDist;
-}
-
-// Test if sequence number a is ahead of sequence number b.
-template <typename T>
-inline bool AheadOf(T a, T b) {
-  MOD_OPS_ASSERT_TYPE_IS_UNSIGNED(T);
-  return a != b && AheadOrAt(a, b);
-}
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_BASE_MOD_OPS_H_
diff --git a/webrtc/base/mod_ops_unittest.cc b/webrtc/base/mod_ops_unittest.cc
deleted file mode 100644
index 13e638f..0000000
--- a/webrtc/base/mod_ops_unittest.cc
+++ /dev/null
@@ -1,172 +0,0 @@
-/*
- *  Copyright (c) 2016 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 "testing/gtest/include/gtest/gtest.h"
-#include "webrtc/base/mod_ops.h"
-
-namespace webrtc {
-class TestModOps : public ::testing::Test {
- protected:
-  // Can't use std::numeric_limits<unsigned long>::max() since
-  // MSVC doesn't support constexpr.
-  static const unsigned long ulmax = ~0ul;  // NOLINT
-};
-
-TEST_F(TestModOps, Add) {
-  const int D = 100;
-  EXPECT_EQ(1u, Add<D>(0, 1));
-  EXPECT_EQ(0u, Add<D>(0, D));
-  for (int i = 0; i < D; ++i)
-    EXPECT_EQ(0u, Add<D>(i, D - i));
-
-  int t = 37;
-  uint8_t a = t;
-  for (int i = 0; i < 256; ++i) {
-    EXPECT_EQ(a, static_cast<uint8_t>(t));
-    t = Add<256>(t, 1);
-    ++a;
-  }
-}
-
-TEST_F(TestModOps, AddLarge) {
-  // NOLINTNEXTLINE
-  const unsigned long D = ulmax - 10ul;  // NOLINT
-  unsigned long l = D - 1ul;             // NOLINT
-  EXPECT_EQ(D - 2ul, Add<D>(l, l));
-  EXPECT_EQ(9ul, Add<D>(l, ulmax));
-  EXPECT_EQ(10ul, Add<D>(0ul, ulmax));
-}
-
-TEST_F(TestModOps, Subtract) {
-  const int D = 100;
-  EXPECT_EQ(99u, Subtract<D>(0, 1));
-  EXPECT_EQ(0u, Subtract<D>(0, D));
-  for (int i = 0; i < D; ++i)
-    EXPECT_EQ(0u, Subtract<D>(i, D + i));
-
-  int t = 37;
-  uint8_t a = t;
-  for (int i = 0; i < 256; ++i) {
-    EXPECT_EQ(a, static_cast<uint8_t>(t));
-    t = Subtract<256>(t, 1);
-    --a;
-  }
-}
-
-TEST_F(TestModOps, SubtractLarge) {
-  // NOLINTNEXTLINE
-  const unsigned long D = ulmax - 10ul;  // NOLINT
-  unsigned long l = D - 1ul;             // NOLINT
-  EXPECT_EQ(0ul, Subtract<D>(l, l));
-  EXPECT_EQ(D - 11ul, Subtract<D>(l, ulmax));
-  EXPECT_EQ(D - 10ul, Subtract<D>(0ul, ulmax));
-}
-
-TEST_F(TestModOps, ForwardDiff) {
-  EXPECT_EQ(0u, ForwardDiff(4711u, 4711u));
-
-  uint8_t x = 0;
-  uint8_t y = 255;
-  for (int i = 0; i < 256; ++i) {
-    EXPECT_EQ(255u, ForwardDiff(x, y));
-    ++x;
-    ++y;
-  }
-
-  int yi = 255;
-  for (int i = 0; i < 256; ++i) {
-    EXPECT_EQ(255u, ForwardDiff<uint8_t>(x, yi));
-    ++x;
-    ++yi;
-  }
-}
-
-TEST_F(TestModOps, ReverseDiff) {
-  EXPECT_EQ(0u, ReverseDiff(4711u, 4711u));
-
-  uint8_t x = 0;
-  uint8_t y = 255;
-  for (int i = 0; i < 256; ++i) {
-    EXPECT_EQ(1u, ReverseDiff(x, y));
-    ++x;
-    ++y;
-  }
-
-  int yi = 255;
-  for (int i = 0; i < 256; ++i) {
-    EXPECT_EQ(1u, ReverseDiff<uint8_t>(x, yi));
-    ++x;
-    ++yi;
-  }
-}
-
-TEST_F(TestModOps, AheadOrAt) {
-  uint8_t x = 0;
-  uint8_t y = 0;
-  EXPECT_TRUE(AheadOrAt(x, y));
-  ++x;
-  EXPECT_TRUE(AheadOrAt(x, y));
-  EXPECT_FALSE(AheadOrAt(y, x));
-  for (int i = 0; i < 256; ++i) {
-    EXPECT_TRUE(AheadOrAt(x, y));
-    ++x;
-    ++y;
-  }
-
-  x = 128;
-  y = 0;
-  EXPECT_TRUE(AheadOrAt(x, y));
-  EXPECT_FALSE(AheadOrAt(y, x));
-
-  x = 129;
-  EXPECT_FALSE(AheadOrAt(x, y));
-  EXPECT_TRUE(AheadOrAt(y, x));
-  EXPECT_TRUE(AheadOrAt<uint16_t>(x, y));
-  EXPECT_FALSE(AheadOrAt<uint16_t>(y, x));
-}
-
-TEST_F(TestModOps, AheadOf) {
-  uint8_t x = 0;
-  uint8_t y = 0;
-  EXPECT_FALSE(AheadOf(x, y));
-  ++x;
-  EXPECT_TRUE(AheadOf(x, y));
-  EXPECT_FALSE(AheadOf(y, x));
-  for (int i = 0; i < 256; ++i) {
-    EXPECT_TRUE(AheadOf(x, y));
-    ++x;
-    ++y;
-  }
-
-  x = 128;
-  y = 0;
-  for (int i = 0; i < 128; ++i) {
-    EXPECT_TRUE(AheadOf(x, y));
-    EXPECT_FALSE(AheadOf(y, x));
-    x++;
-    y++;
-  }
-
-  for (int i = 0; i < 128; ++i) {
-    EXPECT_FALSE(AheadOf(x, y));
-    EXPECT_TRUE(AheadOf(y, x));
-    x++;
-    y++;
-  }
-
-  x = 129;
-  y = 0;
-  EXPECT_FALSE(AheadOf(x, y));
-  EXPECT_TRUE(AheadOf(y, x));
-  EXPECT_TRUE(AheadOf<uint16_t>(x, y));
-  EXPECT_FALSE(AheadOf<uint16_t>(y, x));
-}
-
-}  // namespace webrtc
diff --git a/webrtc/modules/modules.gyp b/webrtc/modules/modules.gyp
index 5deef35..2f88cfc 100644
--- a/webrtc/modules/modules.gyp
+++ b/webrtc/modules/modules.gyp
@@ -363,11 +363,9 @@
             'video_coding/include/mock/mock_vcm_callbacks.h',
             'video_coding/bitrate_adjuster_unittest.cc',
             'video_coding/decoding_state_unittest.cc',
-            'video_coding/histogram_unittest.cc',
             'video_coding/jitter_buffer_unittest.cc',
             'video_coding/jitter_estimator_tests.cc',
             'video_coding/media_optimization_unittest.cc',
-            'video_coding/nack_module_unittest.cc',
             'video_coding/receiver_unittest.cc',
             'video_coding/session_info_unittest.cc',
             'video_coding/timing_unittest.cc',
diff --git a/webrtc/modules/video_coding/histogram.cc b/webrtc/modules/video_coding/histogram.cc
deleted file mode 100644
index 749595b..0000000
--- a/webrtc/modules/video_coding/histogram.cc
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- *  Copyright (c) 2016 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/video_coding/histogram.h"
-
-#include <algorithm>
-
-#include "webrtc/base/mod_ops.h"
-
-namespace webrtc {
-namespace video_coding {
-Histogram::Histogram(size_t num_buckets, size_t max_num_values) {
-  RTC_DCHECK_LE(0u, num_buckets);
-  RTC_DCHECK_LE(0u, max_num_values);
-  buckets_.resize(num_buckets);
-  values_.reserve(max_num_values);
-  index_ = 0;
-}
-
-void Histogram::Add(size_t value) {
-  RTC_DCHECK_GE(value, 0u);
-  value = std::min<size_t>(value, buckets_.size() - 1);
-  if (index_ < values_.size()) {
-    --buckets_[values_[index_]];
-    RTC_DCHECK_LT(values_[index_], buckets_.size());
-    values_[index_] = value;
-  } else {
-    values_.emplace_back(value);
-  }
-
-  ++buckets_[value];
-  index_ = (index_ + 1) % values_.capacity();
-}
-
-size_t Histogram::InverseCdf(float probability) const {
-  RTC_DCHECK_GE(probability, 0.f);
-  RTC_DCHECK_LE(probability, 1.f);
-  RTC_DCHECK_GT(values_.size(), 0ul);
-
-  size_t bucket = 0;
-  float accumulated_probability = 0;
-  while (accumulated_probability < probability && bucket < buckets_.size()) {
-    accumulated_probability +=
-        static_cast<float>(buckets_[bucket]) / values_.size();
-    ++bucket;
-  }
-  return bucket;
-}
-
-size_t Histogram::NumValues() const {
-  return values_.size();
-}
-
-}  // namespace video_coding
-}  // namespace webrtc
diff --git a/webrtc/modules/video_coding/histogram.h b/webrtc/modules/video_coding/histogram.h
deleted file mode 100644
index 7a99a1c..0000000
--- a/webrtc/modules/video_coding/histogram.h
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- *  Copyright (c) 2016 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_VIDEO_CODING_HISTOGRAM_H_
-#define WEBRTC_MODULES_VIDEO_CODING_HISTOGRAM_H_
-
-#include <cstddef>
-#include <vector>
-
-namespace webrtc {
-namespace video_coding {
-class Histogram {
- public:
-  // A discrete histogram where every bucket with range [0, num_buckets).
-  // Values greater or equal to num_buckets will be placed in the last bucket.
-  Histogram(size_t num_buckets, size_t max_num_values);
-
-  // Add a value to the histogram. If there already is max_num_values in the
-  // histogram then the oldest value will be replaced with the new value.
-  void Add(size_t value);
-
-  // Calculates how many buckets have to be summed in order to accumulate at
-  // least the given probability.
-  size_t InverseCdf(float probability) const;
-
-  // How many values that make up this histogram.
-  size_t NumValues() const;
-
- private:
-  // A circular buffer that holds the values that make up the histogram.
-  std::vector<size_t> values_;
-  std::vector<size_t> buckets_;
-  size_t index_;
-};
-
-}  // namespace video_coding
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_VIDEO_CODING_HISTOGRAM_H_
diff --git a/webrtc/modules/video_coding/histogram_unittest.cc b/webrtc/modules/video_coding/histogram_unittest.cc
deleted file mode 100644
index ac79ac4..0000000
--- a/webrtc/modules/video_coding/histogram_unittest.cc
+++ /dev/null
@@ -1,76 +0,0 @@
-/*
- *  Copyright (c) 2016 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 "testing/gtest/include/gtest/gtest.h"
-#include "webrtc/modules/video_coding/histogram.h"
-
-namespace webrtc {
-namespace video_coding {
-
-class TestHistogram : public ::testing::Test {
- protected:
-  TestHistogram() : histogram_(5, 10) {}
-  Histogram histogram_;
-};
-
-TEST_F(TestHistogram, NumValues) {
-  EXPECT_EQ(0ul, histogram_.NumValues());
-  histogram_.Add(0);
-  EXPECT_EQ(1ul, histogram_.NumValues());
-}
-
-TEST_F(TestHistogram, InverseCdf) {
-  histogram_.Add(0);
-  histogram_.Add(1);
-  histogram_.Add(2);
-  histogram_.Add(3);
-  histogram_.Add(4);
-  EXPECT_EQ(5ul, histogram_.NumValues());
-  EXPECT_EQ(1ul, histogram_.InverseCdf(0.2f));
-  EXPECT_EQ(2ul, histogram_.InverseCdf(0.2000001f));
-  EXPECT_EQ(4ul, histogram_.InverseCdf(0.8f));
-
-  histogram_.Add(0);
-  EXPECT_EQ(6ul, histogram_.NumValues());
-  EXPECT_EQ(1ul, histogram_.InverseCdf(0.2f));
-  EXPECT_EQ(1ul, histogram_.InverseCdf(0.2000001f));
-}
-
-TEST_F(TestHistogram, ReplaceOldValues) {
-  histogram_.Add(0);
-  histogram_.Add(0);
-  histogram_.Add(0);
-  histogram_.Add(0);
-  histogram_.Add(0);
-  histogram_.Add(1);
-  histogram_.Add(1);
-  histogram_.Add(1);
-  histogram_.Add(1);
-  histogram_.Add(1);
-  EXPECT_EQ(10ul, histogram_.NumValues());
-  EXPECT_EQ(1ul, histogram_.InverseCdf(0.5f));
-  EXPECT_EQ(2ul, histogram_.InverseCdf(0.5000001f));
-
-  histogram_.Add(4);
-  histogram_.Add(4);
-  histogram_.Add(4);
-  histogram_.Add(4);
-  EXPECT_EQ(10ul, histogram_.NumValues());
-  EXPECT_EQ(1ul, histogram_.InverseCdf(0.1f));
-  EXPECT_EQ(2ul, histogram_.InverseCdf(0.5f));
-
-  histogram_.Add(20);
-  EXPECT_EQ(10ul, histogram_.NumValues());
-  EXPECT_EQ(2ul, histogram_.InverseCdf(0.5f));
-  EXPECT_EQ(5ul, histogram_.InverseCdf(0.5000001f));
-}
-
-}  // namespace video_coding
-}  // namespace webrtc
diff --git a/webrtc/modules/video_coding/include/video_coding_defines.h b/webrtc/modules/video_coding/include/video_coding_defines.h
index 4fe8c79..7d084c8 100644
--- a/webrtc/modules/video_coding/include/video_coding_defines.h
+++ b/webrtc/modules/video_coding/include/video_coding_defines.h
@@ -11,8 +11,6 @@
 #ifndef WEBRTC_MODULES_VIDEO_CODING_INCLUDE_VIDEO_CODING_DEFINES_H_
 #define WEBRTC_MODULES_VIDEO_CODING_INCLUDE_VIDEO_CODING_DEFINES_H_
 
-#include <vector>
-
 #include "webrtc/modules/include/module_common_types.h"
 #include "webrtc/typedefs.h"
 #include "webrtc/video_frame.h"
@@ -162,8 +160,6 @@
 // Callback class used for telling the user about which packet sequence numbers
 // are currently
 // missing and need to be resent.
-// TODO(philipel): Deprecate VCMPacketRequestCallback
-//                 and use NackSender instead.
 class VCMPacketRequestCallback {
  public:
   virtual int32_t ResendPackets(const uint16_t* sequenceNumbers,
@@ -173,22 +169,6 @@
   virtual ~VCMPacketRequestCallback() {}
 };
 
-class NackSender {
- public:
-  virtual void SendNack(const std::vector<uint16_t>& sequence_numbers) = 0;
-
- protected:
-  virtual ~NackSender() {}
-};
-
-class KeyFrameRequestSender {
- public:
-  virtual void RequestKeyFrame() = 0;
-
- protected:
-  virtual ~KeyFrameRequestSender() {}
-};
-
 // Callback used to inform the user of the the desired resolution
 // as subscribed by Media Optimization (Quality Modes)
 class VCMQMSettingsCallback {
diff --git a/webrtc/modules/video_coding/nack_module.cc b/webrtc/modules/video_coding/nack_module.cc
deleted file mode 100644
index 319a902..0000000
--- a/webrtc/modules/video_coding/nack_module.cc
+++ /dev/null
@@ -1,257 +0,0 @@
-/*
- *  Copyright (c) 2016 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 <algorithm>
-#include <limits>
-
-#include "webrtc/modules/video_coding/nack_module.h"
-
-#include "webrtc/base/checks.h"
-#include "webrtc/base/logging.h"
-#include "webrtc/base/mod_ops.h"
-#include "webrtc/modules/utility/include/process_thread.h"
-
-namespace webrtc {
-
-namespace {
-const int kMaxPacketAge = 10000;
-const int kMaxNackPackets = 1000;
-const int kDefaultRttMs = 100;
-const int kMaxNackRetries = 10;
-const int kProcessFrequency = 50;
-const int kProcessIntervalMs = 1000 / kProcessFrequency;
-const int kMaxReorderedPackets = 128;
-const int kNumReorderingBuckets = 10;
-}  // namespace
-
-NackModule::NackInfo::NackInfo()
-    : seq_num(0), send_at_seq_num(0), sent_at_time(-1), retries(0) {}
-
-NackModule::NackInfo::NackInfo(uint16_t seq_num, uint16_t send_at_seq_num)
-    : seq_num(seq_num),
-      send_at_seq_num(send_at_seq_num),
-      sent_at_time(-1),
-      retries(0) {}
-
-NackModule::NackModule(Clock* clock,
-                       NackSender* nack_sender,
-                       KeyFrameRequestSender* keyframe_request_sender)
-    : clock_(clock),
-      nack_sender_(nack_sender),
-      keyframe_request_sender_(keyframe_request_sender),
-      reordering_histogram_(kNumReorderingBuckets, kMaxReorderedPackets),
-      running_(true),
-      initialized_(false),
-      rtt_ms_(kDefaultRttMs),
-      last_seq_num_(0),
-      next_process_time_ms_(-1) {
-  RTC_DCHECK(clock_);
-  RTC_DCHECK(nack_sender_);
-  RTC_DCHECK(keyframe_request_sender_);
-}
-
-void NackModule::OnReceivedPacket(const VCMPacket& packet) {
-  rtc::CritScope lock(&crit_);
-  if (!running_)
-    return;
-  uint16_t seq_num = packet.seqNum;
-  // TODO(philipel): When the packet includes information whether it is
-  //                 retransmitted or not, use that value instead. For
-  //                 now set it to true, which will cause the reordering
-  //                 statistics to never be updated.
-  bool is_retransmitted = true;
-  bool is_keyframe = packet.isFirstPacket && packet.frameType == kVideoFrameKey;
-
-  if (!initialized_) {
-    last_seq_num_ = seq_num;
-    if (is_keyframe)
-      keyframe_list_.insert(seq_num);
-    initialized_ = true;
-    return;
-  }
-
-  if (seq_num == last_seq_num_)
-    return;
-
-  if (AheadOf(last_seq_num_, seq_num)) {
-    // An out of order packet has been received.
-    nack_list_.erase(seq_num);
-    if (!is_retransmitted)
-      UpdateReorderingStatistics(seq_num);
-    return;
-  } else {
-    AddPacketsToNack(last_seq_num_ + 1, seq_num);
-    last_seq_num_ = seq_num;
-
-    // Keep track of new keyframes.
-    if (is_keyframe)
-      keyframe_list_.insert(seq_num);
-
-    // And remove old ones so we don't accumulate keyframes.
-    auto it = keyframe_list_.lower_bound(seq_num - kMaxPacketAge);
-    if (it != keyframe_list_.begin())
-      keyframe_list_.erase(keyframe_list_.begin(), it);
-
-    // Are there any nacks that are waiting for this seq_num.
-    std::vector<uint16_t> nack_batch = GetNackBatch(kSeqNumOnly);
-    if (!nack_batch.empty())
-      nack_sender_->SendNack(nack_batch);
-  }
-}
-
-void NackModule::ClearUpTo(uint16_t seq_num) {
-  rtc::CritScope lock(&crit_);
-  nack_list_.erase(nack_list_.begin(), nack_list_.lower_bound(seq_num));
-  keyframe_list_.erase(keyframe_list_.begin(),
-                       keyframe_list_.lower_bound(seq_num));
-}
-
-void NackModule::UpdateRtt(int64_t rtt_ms) {
-  rtc::CritScope lock(&crit_);
-  rtt_ms_ = rtt_ms;
-}
-
-void NackModule::Stop() {
-  rtc::CritScope lock(&crit_);
-  running_ = false;
-}
-
-int64_t NackModule::TimeUntilNextProcess() {
-  rtc::CritScope lock(&crit_);
-  return std::max<int64_t>(next_process_time_ms_ - clock_->TimeInMilliseconds(),
-                           0);
-}
-
-void NackModule::Process() {
-  rtc::CritScope lock(&crit_);
-  if (!running_)
-    return;
-
-  // Update the next_process_time_ms_ in intervals to achieve
-  // the targeted frequency over time. Also add multiple intervals
-  // in case of a skip in time as to not make uneccessary
-  // calls to Process in order to catch up.
-  int64_t now_ms = clock_->TimeInMilliseconds();
-  if (next_process_time_ms_ == -1) {
-    next_process_time_ms_ = now_ms + kProcessIntervalMs;
-  } else {
-    next_process_time_ms_ = next_process_time_ms_ + kProcessIntervalMs +
-                            (now_ms - next_process_time_ms_) /
-                                kProcessIntervalMs * kProcessIntervalMs;
-  }
-
-  std::vector<uint16_t> nack_batch = GetNackBatch(kTimeOnly);
-  if (!nack_batch.empty() && nack_sender_ != nullptr)
-    nack_sender_->SendNack(nack_batch);
-}
-
-bool NackModule::RemovePacketsUntilKeyFrame() {
-  while (!keyframe_list_.empty()) {
-    auto it = nack_list_.lower_bound(*keyframe_list_.begin());
-
-    if (it != nack_list_.begin()) {
-      // We have found a keyframe that actually is newer than at least one
-      // packet in the nack list.
-      RTC_DCHECK(it != nack_list_.end());
-      nack_list_.erase(nack_list_.begin(), it);
-      return true;
-    }
-
-    // If this keyframe is so old it does not remove any packets from the list,
-    // remove it from the list of keyframes and try the next keyframe.
-    keyframe_list_.erase(keyframe_list_.begin());
-  }
-  return false;
-}
-
-void NackModule::AddPacketsToNack(uint16_t seq_num_start,
-                                  uint16_t seq_num_end) {
-  // Remove old packets.
-  auto it = nack_list_.lower_bound(seq_num_end - kMaxPacketAge);
-  nack_list_.erase(nack_list_.begin(), it);
-
-  // If the nack list is too large, remove packets from the nack list until
-  // the latest first packet of a keyframe. If the list is still too large,
-  // clear it and request a keyframe.
-  uint16_t num_new_nacks = ForwardDiff(seq_num_start, seq_num_end);
-  if (nack_list_.size() + num_new_nacks > kMaxNackPackets) {
-    while (RemovePacketsUntilKeyFrame() &&
-           nack_list_.size() + num_new_nacks > kMaxNackPackets) {
-    }
-
-    if (nack_list_.size() + num_new_nacks > kMaxNackPackets) {
-      nack_list_.clear();
-      LOG(LS_WARNING) << "NACK list full, clearing NACK"
-                         " list and requesting keyframe.";
-      keyframe_request_sender_->RequestKeyFrame();
-      return;
-    }
-  }
-
-  for (uint16_t seq_num = seq_num_start; seq_num != seq_num_end; ++seq_num) {
-    NackInfo nack_info(seq_num, seq_num + WaitNumberOfPackets(0.5));
-    RTC_DCHECK(nack_list_.find(seq_num) == nack_list_.end());
-    nack_list_[seq_num] = nack_info;
-  }
-}
-
-std::vector<uint16_t> NackModule::GetNackBatch(NackFilterOptions options) {
-  bool consider_seq_num = options != kTimeOnly;
-  bool consider_timestamp = options != kSeqNumOnly;
-  int64_t now_ms = clock_->TimeInMilliseconds();
-  std::vector<uint16_t> nack_batch;
-  auto it = nack_list_.begin();
-  while (it != nack_list_.end()) {
-    if (consider_seq_num && it->second.sent_at_time == -1 &&
-        AheadOrAt(last_seq_num_, it->second.send_at_seq_num)) {
-      nack_batch.emplace_back(it->second.seq_num);
-      ++it->second.retries;
-      it->second.sent_at_time = now_ms;
-      if (it->second.retries >= kMaxNackRetries) {
-        LOG(LS_WARNING) << "Sequence number " << it->second.seq_num
-                        << " removed from NACK list due to max retries.";
-        it = nack_list_.erase(it);
-      } else {
-        ++it;
-      }
-      continue;
-    }
-
-    if (consider_timestamp && it->second.sent_at_time + rtt_ms_ <= now_ms) {
-      nack_batch.emplace_back(it->second.seq_num);
-      ++it->second.retries;
-      it->second.sent_at_time = now_ms;
-      if (it->second.retries >= kMaxNackRetries) {
-        LOG(LS_WARNING) << "Sequence number " << it->second.seq_num
-                        << " removed from NACK list due to max retries.";
-        it = nack_list_.erase(it);
-      } else {
-        ++it;
-      }
-      continue;
-    }
-    ++it;
-  }
-  return nack_batch;
-}
-
-void NackModule::UpdateReorderingStatistics(uint16_t seq_num) {
-  RTC_DCHECK(AheadOf(last_seq_num_, seq_num));
-  uint16_t diff = ReverseDiff(last_seq_num_, seq_num);
-  reordering_histogram_.Add(diff);
-}
-
-int NackModule::WaitNumberOfPackets(float probability) const {
-  if (reordering_histogram_.NumValues() == 0)
-    return 0;
-  return reordering_histogram_.InverseCdf(probability);
-}
-
-}  // namespace webrtc
diff --git a/webrtc/modules/video_coding/nack_module.h b/webrtc/modules/video_coding/nack_module.h
deleted file mode 100644
index 32692be..0000000
--- a/webrtc/modules/video_coding/nack_module.h
+++ /dev/null
@@ -1,101 +0,0 @@
-/*
- *  Copyright (c) 2016 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_VIDEO_CODING_NACK_MODULE_H_
-#define WEBRTC_MODULES_VIDEO_CODING_NACK_MODULE_H_
-
-#include <map>
-#include <vector>
-#include <set>
-
-#include "webrtc/base/criticalsection.h"
-#include "webrtc/base/mod_ops.h"
-#include "webrtc/base/thread_annotations.h"
-#include "webrtc/modules/include/module.h"
-#include "webrtc/modules/video_coding/include/video_coding_defines.h"
-#include "webrtc/modules/video_coding/packet.h"
-#include "webrtc/modules/video_coding/histogram.h"
-#include "webrtc/system_wrappers/include/clock.h"
-
-namespace webrtc {
-
-class NackModule : public Module {
- public:
-  NackModule(Clock* clock,
-             NackSender* nack_sender,
-             KeyFrameRequestSender* keyframe_request_sender);
-
-  void OnReceivedPacket(const VCMPacket& packet);
-  void ClearUpTo(uint16_t seq_num);
-  void UpdateRtt(int64_t rtt_ms);
-  void Stop();
-
-  // Module implementation
-  int64_t TimeUntilNextProcess() override;
-  void Process() override;
-
- private:
-  // Which fields to consider when deciding which packet to nack in
-  // GetNackBatch.
-  enum NackFilterOptions { kSeqNumOnly, kTimeOnly, kSeqNumAndTime };
-
-  // This class holds the sequence number of the packet that is in the nack list
-  // as well as the meta data about when it should be nacked and how many times
-  // we have tried to nack this packet.
-  struct NackInfo {
-    NackInfo();
-    NackInfo(uint16_t seq_num, uint16_t send_at_seq_num);
-
-    uint16_t seq_num;
-    uint16_t send_at_seq_num;
-    int64_t sent_at_time;
-    int retries;
-  };
-
-  struct SeqNumComparator {
-    bool operator()(uint16_t s1, uint16_t s2) const { return AheadOf(s2, s1); }
-  };
-
-  void AddPacketsToNack(uint16_t seq_num_start, uint16_t seq_num_end)
-      EXCLUSIVE_LOCKS_REQUIRED(crit_);
-
-  // Removes packets from the nack list until the next keyframe. Returns true
-  // if packets were removed.
-  bool RemovePacketsUntilKeyFrame() EXCLUSIVE_LOCKS_REQUIRED(crit_);
-  std::vector<uint16_t> GetNackBatch(NackFilterOptions options)
-      EXCLUSIVE_LOCKS_REQUIRED(crit_);
-
-  // Update the reordering distribution.
-  void UpdateReorderingStatistics(uint16_t seq_num)
-      EXCLUSIVE_LOCKS_REQUIRED(crit_);
-
-  // Returns how many packets we have to wait in order to receive the packet
-  // with probability |probabilty| or higher.
-  int WaitNumberOfPackets(float probability) const
-      EXCLUSIVE_LOCKS_REQUIRED(crit_);
-
-  rtc::CriticalSection crit_;
-  Clock* const clock_;
-  NackSender* const nack_sender_;
-  KeyFrameRequestSender* const keyframe_request_sender_;
-
-  std::map<uint16_t, NackInfo, SeqNumComparator> nack_list_ GUARDED_BY(crit_);
-  std::set<uint16_t, SeqNumComparator> keyframe_list_ GUARDED_BY(crit_);
-  video_coding::Histogram reordering_histogram_ GUARDED_BY(crit_);
-  bool running_ GUARDED_BY(crit_);
-  bool initialized_ GUARDED_BY(crit_);
-  int64_t rtt_ms_ GUARDED_BY(crit_);
-  uint16_t last_seq_num_ GUARDED_BY(crit_);
-  int64_t next_process_time_ms_ GUARDED_BY(crit_);
-};
-
-}  // namespace webrtc
-
-#endif  // WEBRTC_MODULES_VIDEO_CODING_NACK_MODULE_H_
diff --git a/webrtc/modules/video_coding/nack_module_unittest.cc b/webrtc/modules/video_coding/nack_module_unittest.cc
deleted file mode 100644
index 189a1be..0000000
--- a/webrtc/modules/video_coding/nack_module_unittest.cc
+++ /dev/null
@@ -1,292 +0,0 @@
-/*
- *  Copyright (c) 2016 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 <cstring>
-#include "testing/gtest/include/gtest/gtest.h"
-#include "webrtc/modules/video_coding/include/video_coding_defines.h"
-#include "webrtc/modules/video_coding/nack_module.h"
-#include "webrtc/system_wrappers/include/clock.h"
-#include "webrtc/base/mod_ops.h"
-
-namespace webrtc {
-class TestNackModule : public ::testing::Test,
-                       public NackSender,
-                       public KeyFrameRequestSender {
- protected:
-  TestNackModule()
-      : clock_(new SimulatedClock(0)),
-        nack_module_(clock_.get(), this, this),
-        keyframes_requested_(0) {}
-
-  void SendNack(const std::vector<uint16_t>& sequence_numbers) override {
-    sent_nacks_.insert(sent_nacks_.end(), sequence_numbers.begin(),
-                       sequence_numbers.end());
-  }
-
-  void RequestKeyFrame() override { ++keyframes_requested_; }
-
-  std::unique_ptr<SimulatedClock> clock_;
-  NackModule nack_module_;
-  std::vector<uint16_t> sent_nacks_;
-  int keyframes_requested_;
-};
-
-TEST_F(TestNackModule, NackOnePacket) {
-  VCMPacket packet;
-  packet.seqNum = 1;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 3;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(1u, sent_nacks_.size());
-  EXPECT_EQ(2, sent_nacks_[0]);
-}
-
-TEST_F(TestNackModule, WrappingSeqNum) {
-  VCMPacket packet;
-  packet.seqNum = 0xfffe;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 1;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(2u, sent_nacks_.size());
-  EXPECT_EQ(0xffff, sent_nacks_[0]);
-  EXPECT_EQ(0, sent_nacks_[1]);
-}
-
-TEST_F(TestNackModule, WrappingSeqNumClearToKeyframe) {
-  VCMPacket packet;
-  packet.seqNum = 0xfffe;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 1;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(2u, sent_nacks_.size());
-  EXPECT_EQ(0xffff, sent_nacks_[0]);
-  EXPECT_EQ(0, sent_nacks_[1]);
-
-  sent_nacks_.clear();
-  packet.frameType = kVideoFrameKey;
-  packet.isFirstPacket = true;
-  packet.seqNum = 2;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(0u, sent_nacks_.size());
-
-  packet.seqNum = 501;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(498u, sent_nacks_.size());
-  for (int seq_num = 3; seq_num < 501; ++seq_num)
-    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 3]);
-
-  sent_nacks_.clear();
-  packet.frameType = kVideoFrameDelta;
-  packet.seqNum = 1001;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(499u, sent_nacks_.size());
-  for (int seq_num = 502; seq_num < 1001; ++seq_num)
-    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 502]);
-
-  sent_nacks_.clear();
-  clock_->AdvanceTimeMilliseconds(100);
-  nack_module_.Process();
-  EXPECT_EQ(999u, sent_nacks_.size());
-  EXPECT_EQ(0xffff, sent_nacks_[0]);
-  EXPECT_EQ(0, sent_nacks_[1]);
-  for (int seq_num = 3; seq_num < 501; ++seq_num)
-    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 1]);
-  for (int seq_num = 502; seq_num < 1001; ++seq_num)
-    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 2]);
-
-  // Adding packet 1004 will cause the nack list to reach it's max limit.
-  // It will then clear all nacks up to the next keyframe (seq num 2),
-  // thus removing 0xffff and 0 from the nack list.
-  sent_nacks_.clear();
-  packet.seqNum = 1004;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(2u, sent_nacks_.size());
-  EXPECT_EQ(1002, sent_nacks_[0]);
-  EXPECT_EQ(1003, sent_nacks_[1]);
-
-  sent_nacks_.clear();
-  clock_->AdvanceTimeMilliseconds(100);
-  nack_module_.Process();
-  EXPECT_EQ(999u, sent_nacks_.size());
-  for (int seq_num = 3; seq_num < 501; ++seq_num)
-    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 3]);
-  for (int seq_num = 502; seq_num < 1001; ++seq_num)
-    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 4]);
-
-  // Adding packet 1007 will cause the nack module to overflow again, thus
-  // clearing everything up to 501 which is the next keyframe.
-  packet.seqNum = 1007;
-  nack_module_.OnReceivedPacket(packet);
-  sent_nacks_.clear();
-  clock_->AdvanceTimeMilliseconds(100);
-  nack_module_.Process();
-  EXPECT_EQ(503u, sent_nacks_.size());
-  for (int seq_num = 502; seq_num < 1001; ++seq_num)
-    EXPECT_EQ(seq_num, sent_nacks_[seq_num - 502]);
-  EXPECT_EQ(1005, sent_nacks_[501]);
-  EXPECT_EQ(1006, sent_nacks_[502]);
-}
-
-TEST_F(TestNackModule, DontBurstOnTimeSkip) {
-  nack_module_.Process();
-  clock_->AdvanceTimeMilliseconds(20);
-  EXPECT_EQ(0, nack_module_.TimeUntilNextProcess());
-  nack_module_.Process();
-
-  clock_->AdvanceTimeMilliseconds(100);
-  EXPECT_EQ(0, nack_module_.TimeUntilNextProcess());
-  nack_module_.Process();
-  EXPECT_EQ(20, nack_module_.TimeUntilNextProcess());
-
-  clock_->AdvanceTimeMilliseconds(19);
-  EXPECT_EQ(1, nack_module_.TimeUntilNextProcess());
-  clock_->AdvanceTimeMilliseconds(2);
-  nack_module_.Process();
-  EXPECT_EQ(19, nack_module_.TimeUntilNextProcess());
-
-  clock_->AdvanceTimeMilliseconds(19);
-  EXPECT_EQ(0, nack_module_.TimeUntilNextProcess());
-  nack_module_.Process();
-
-  clock_->AdvanceTimeMilliseconds(21);
-  EXPECT_EQ(0, nack_module_.TimeUntilNextProcess());
-  nack_module_.Process();
-  EXPECT_EQ(19, nack_module_.TimeUntilNextProcess());
-}
-
-TEST_F(TestNackModule, ResendNack) {
-  VCMPacket packet;
-  packet.seqNum = 1;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 3;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(1u, sent_nacks_.size());
-  EXPECT_EQ(2, sent_nacks_[0]);
-
-  // Default RTT is 100
-  clock_->AdvanceTimeMilliseconds(99);
-  nack_module_.Process();
-  EXPECT_EQ(1u, sent_nacks_.size());
-
-  clock_->AdvanceTimeMilliseconds(1);
-  nack_module_.Process();
-  EXPECT_EQ(2u, sent_nacks_.size());
-
-  nack_module_.UpdateRtt(50);
-  clock_->AdvanceTimeMilliseconds(100);
-  nack_module_.Process();
-  EXPECT_EQ(3u, sent_nacks_.size());
-
-  clock_->AdvanceTimeMilliseconds(50);
-  nack_module_.Process();
-  EXPECT_EQ(4u, sent_nacks_.size());
-
-  packet.seqNum = 2;
-  nack_module_.OnReceivedPacket(packet);
-  clock_->AdvanceTimeMilliseconds(50);
-  nack_module_.Process();
-  EXPECT_EQ(4u, sent_nacks_.size());
-}
-
-TEST_F(TestNackModule, ResendPacketMaxRetries) {
-  VCMPacket packet;
-  packet.seqNum = 1;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 3;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(1u, sent_nacks_.size());
-  EXPECT_EQ(2, sent_nacks_[0]);
-
-  for (size_t retries = 1; retries < 10; ++retries) {
-    clock_->AdvanceTimeMilliseconds(100);
-    nack_module_.Process();
-    EXPECT_EQ(retries + 1, sent_nacks_.size());
-  }
-
-  clock_->AdvanceTimeMilliseconds(100);
-  nack_module_.Process();
-  EXPECT_EQ(10u, sent_nacks_.size());
-}
-
-TEST_F(TestNackModule, TooLargeNackList) {
-  VCMPacket packet;
-  packet.seqNum = 0;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 1001;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(1000u, sent_nacks_.size());
-  EXPECT_EQ(0, keyframes_requested_);
-  packet.seqNum = 1003;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(1000u, sent_nacks_.size());
-  EXPECT_EQ(1, keyframes_requested_);
-  packet.seqNum = 1004;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(1000u, sent_nacks_.size());
-  EXPECT_EQ(1, keyframes_requested_);
-}
-
-TEST_F(TestNackModule, TooLargeNackListWithKeyFrame) {
-  VCMPacket packet;
-  packet.seqNum = 0;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 1;
-  packet.isFirstPacket = true;
-  packet.frameType = kVideoFrameKey;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 1001;
-  packet.isFirstPacket = false;
-  packet.frameType = kVideoFrameKey;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(999u, sent_nacks_.size());
-  EXPECT_EQ(0, keyframes_requested_);
-  packet.seqNum = 1003;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(1000u, sent_nacks_.size());
-  EXPECT_EQ(0, keyframes_requested_);
-  packet.seqNum = 1005;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(1000u, sent_nacks_.size());
-  EXPECT_EQ(1, keyframes_requested_);
-}
-
-TEST_F(TestNackModule, ClearUpTo) {
-  VCMPacket packet;
-  packet.seqNum = 0;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 100;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(99u, sent_nacks_.size());
-
-  sent_nacks_.clear();
-  clock_->AdvanceTimeMilliseconds(100);
-  nack_module_.ClearUpTo(50);
-  nack_module_.Process();
-  EXPECT_EQ(50u, sent_nacks_.size());
-  EXPECT_EQ(50, sent_nacks_[0]);
-}
-
-TEST_F(TestNackModule, ClearUpToWrap) {
-  VCMPacket packet;
-  packet.seqNum = 0xfff0;
-  nack_module_.OnReceivedPacket(packet);
-  packet.seqNum = 0xf;
-  nack_module_.OnReceivedPacket(packet);
-  EXPECT_EQ(30u, sent_nacks_.size());
-
-  sent_nacks_.clear();
-  clock_->AdvanceTimeMilliseconds(100);
-  nack_module_.ClearUpTo(0);
-  nack_module_.Process();
-  EXPECT_EQ(15u, sent_nacks_.size());
-  EXPECT_EQ(0, sent_nacks_[0]);
-}
-
-}  // namespace webrtc
diff --git a/webrtc/modules/video_coding/video_coding.gypi b/webrtc/modules/video_coding/video_coding.gypi
index 02c9c6b..94028a9 100644
--- a/webrtc/modules/video_coding/video_coding.gypi
+++ b/webrtc/modules/video_coding/video_coding.gypi
@@ -36,7 +36,6 @@
         'frame_buffer.h',
         'generic_decoder.h',
         'generic_encoder.h',
-        'histogram.h',
         'inter_frame_delay.h',
         'internal_defines.h',
         'jitter_buffer.h',
@@ -45,7 +44,6 @@
         'media_opt_util.h',
         'media_optimization.h',
         'nack_fec_tables.h',
-        'nack_module.h',
         'packet.h',
         'qm_select_data.h',
         'qm_select.h',
@@ -67,12 +65,10 @@
         'generic_decoder.cc',
         'generic_encoder.cc',
         'inter_frame_delay.cc',
-        'histogram.cc',
         'jitter_buffer.cc',
         'jitter_estimator.cc',
         'media_opt_util.cc',
         'media_optimization.cc',
-        'nack_module.cc',
         'packet.cc',
         'qm_select.cc',
         'receiver.cc',