Revert "APM: log both applied and recommended input volume stats"

This reverts commit 8d7273357d92fab881561d886ce8dfe94e6e2238.

Reason for revert: revert needed to land https://webrtc-review.googlesource.com/c/src/+/280600

Original change's description:
> APM: log both applied and recommended input volume stats
>
> This CL replaces the existing `WebRTC.Audio.ApmAnalogGain.*` stats
> with `WebRTC.Audio.Apm.AppliedInputVolume.*` and adds the
> `WebRTC.Audio.Apm.RecommendedInputVolume.*` stats.
>
> Bug: webrtc:7494
> Change-Id: I70be710d20b1589fc814cbce3d3329ac1500686f
> Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/280220
> Reviewed-by: Hanna Silen <silen@webrtc.org>
> Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
> Cr-Commit-Position: refs/heads/main@{#38468}

Bug: webrtc:7494
Change-Id: I4a2acfd5a983d9397932b2879cfa057deaf0eb2b
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/280581
Commit-Queue: Alessio Bazzica <alessiob@webrtc.org>
Auto-Submit: Alessio Bazzica <alessiob@webrtc.org>
Bot-Commit: rubber-stamper@appspot.gserviceaccount.com <rubber-stamper@appspot.gserviceaccount.com>
Cr-Commit-Position: refs/heads/main@{#38476}
diff --git a/modules/audio_processing/agc2/BUILD.gn b/modules/audio_processing/agc2/BUILD.gn
index 0e20ae6..bc15076 100644
--- a/modules/audio_processing/agc2/BUILD.gn
+++ b/modules/audio_processing/agc2/BUILD.gn
@@ -436,9 +436,7 @@
   sources = [ "input_volume_stats_reporter_unittest.cc" ]
   deps = [
     ":input_volume_stats_reporter",
-    "../../../rtc_base:stringutils",
     "../../../system_wrappers:metrics",
     "../../../test:test_support",
   ]
-  absl_deps = [ "//third_party/abseil-cpp/absl/strings" ]
 }
diff --git a/modules/audio_processing/agc2/input_volume_stats_reporter.cc b/modules/audio_processing/agc2/input_volume_stats_reporter.cc
index 6d70186..4a8b016 100644
--- a/modules/audio_processing/agc2/input_volume_stats_reporter.cc
+++ b/modules/audio_processing/agc2/input_volume_stats_reporter.cc
@@ -19,8 +19,6 @@
 namespace webrtc {
 namespace {
 
-using InputVolumeType = InputVolumeStatsReporter::InputVolumeType;
-
 constexpr int kFramesIn60Seconds = 6000;
 constexpr int kMinInputVolume = 0;
 constexpr int kMaxInputVolume = 255;
@@ -37,102 +35,9 @@
   return std::round(static_cast<float>(sum_updates) /
                     static_cast<float>(num_updates));
 }
-
-metrics::Histogram* CreateRateHistogram(absl::string_view name) {
-  return metrics::HistogramFactoryGetCounts(
-      name, /*min=*/1, /*max=*/kFramesIn60Seconds, /*bucket_count=*/50);
-}
-
-metrics::Histogram* CreateAverageHistogram(absl::string_view name) {
-  return metrics::HistogramFactoryGetCounts(name, /*min=*/1, /*max=*/kMaxUpdate,
-                                            /*bucket_count=*/50);
-}
-
-metrics::Histogram* CreateDecreaseRateHistogram(
-    InputVolumeType input_volume_type) {
-  switch (input_volume_type) {
-    case InputVolumeType::kApplied:
-      return CreateRateHistogram(
-          "WebRTC.Audio.Apm.AppliedInputVolume.DecreaseRate");
-    case InputVolumeType::kRecommended:
-      return CreateRateHistogram(
-          "WebRTC.Audio.Apm.RecommendedInputVolume.DecreaseRate");
-  }
-}
-
-metrics::Histogram* CreateDecreaseAverageHistogram(
-    InputVolumeType input_volume_type) {
-  switch (input_volume_type) {
-    case InputVolumeType::kApplied:
-      return CreateAverageHistogram(
-          "WebRTC.Audio.Apm.AppliedInputVolume.DecreaseAverage");
-    case InputVolumeType::kRecommended:
-      return CreateAverageHistogram(
-          "WebRTC.Audio.Apm.RecommendedInputVolume.DecreaseAverage");
-  }
-}
-
-metrics::Histogram* CreateIncreaseRateHistogram(
-    InputVolumeType input_volume_type) {
-  switch (input_volume_type) {
-    case InputVolumeType::kApplied:
-      return CreateRateHistogram(
-          "WebRTC.Audio.Apm.AppliedInputVolume.IncreaseRate");
-    case InputVolumeType::kRecommended:
-      return CreateRateHistogram(
-          "WebRTC.Audio.Apm.RecommendedInputVolume.IncreaseRate");
-  }
-}
-
-metrics::Histogram* CreateIncreaseAverageHistogram(
-    InputVolumeType input_volume_type) {
-  switch (input_volume_type) {
-    case InputVolumeType::kApplied:
-      return CreateAverageHistogram(
-          "WebRTC.Audio.Apm.AppliedInputVolume.IncreaseAverage");
-    case InputVolumeType::kRecommended:
-      return CreateAverageHistogram(
-          "WebRTC.Audio.Apm.RecommendedInputVolume.IncreaseAverage");
-  }
-}
-
-metrics::Histogram* CreateUpdateRateHistogram(
-    InputVolumeType input_volume_type) {
-  switch (input_volume_type) {
-    case InputVolumeType::kApplied:
-      return CreateRateHistogram(
-          "WebRTC.Audio.Apm.AppliedInputVolume.UpdateRate");
-    case InputVolumeType::kRecommended:
-      return CreateRateHistogram(
-          "WebRTC.Audio.Apm.RecommendedInputVolume.UpdateRate");
-  }
-}
-
-metrics::Histogram* CreateUpdateAverageHistogram(
-    InputVolumeType input_volume_type) {
-  switch (input_volume_type) {
-    case InputVolumeType::kApplied:
-      return CreateAverageHistogram(
-          "WebRTC.Audio.Apm.AppliedInputVolume.UpdateAverage");
-    case InputVolumeType::kRecommended:
-      return CreateAverageHistogram(
-          "WebRTC.Audio.Apm.RecommendedInputVolume.UpdateAverage");
-  }
-}
-
 }  // namespace
 
-InputVolumeStatsReporter::InputVolumeStatsReporter(
-    InputVolumeType input_volume_type)
-    : decrease_rate_histogram_(CreateDecreaseRateHistogram(input_volume_type)),
-      decrease_average_histogram_(
-          CreateDecreaseAverageHistogram(input_volume_type)),
-      increase_rate_histogram_(CreateIncreaseRateHistogram(input_volume_type)),
-      increase_average_histogram_(
-          CreateIncreaseAverageHistogram(input_volume_type)),
-      update_rate_histogram_(CreateUpdateRateHistogram(input_volume_type)),
-      update_average_histogram_(
-          CreateUpdateAverageHistogram(input_volume_type)) {}
+InputVolumeStatsReporter::InputVolumeStatsReporter() = default;
 
 InputVolumeStatsReporter::~InputVolumeStatsReporter() = default;
 
@@ -169,19 +74,47 @@
   const float average_update = ComputeAverageUpdate(
       volume_update_stats_.sum_decreases + volume_update_stats_.sum_increases,
       num_updates);
-  metrics::HistogramAdd(decrease_rate_histogram_,
-                        volume_update_stats_.num_decreases);
+  RTC_HISTOGRAM_COUNTS_LINEAR(
+      /*name=*/"WebRTC.Audio.ApmAnalogGainDecreaseRate",
+      /*sample=*/volume_update_stats_.num_decreases,
+      /*min=*/1,
+      /*max=*/kFramesIn60Seconds,
+      /*bucket_count=*/50);
   if (volume_update_stats_.num_decreases > 0) {
-    metrics::HistogramAdd(decrease_average_histogram_, average_decrease);
+    RTC_HISTOGRAM_COUNTS_LINEAR(
+        /*name=*/"WebRTC.Audio.ApmAnalogGainDecreaseAverage",
+        /*sample=*/average_decrease,
+        /*min=*/1,
+        /*max=*/kMaxUpdate,
+        /*bucket_count=*/50);
   }
-  metrics::HistogramAdd(increase_rate_histogram_,
-                        volume_update_stats_.num_increases);
+  RTC_HISTOGRAM_COUNTS_LINEAR(
+      /*name=*/"WebRTC.Audio.ApmAnalogGainIncreaseRate",
+      /*sample=*/volume_update_stats_.num_increases,
+      /*min=*/1,
+      /*max=*/kFramesIn60Seconds,
+      /*bucket_count=*/50);
   if (volume_update_stats_.num_increases > 0) {
-    metrics::HistogramAdd(increase_average_histogram_, average_increase);
+    RTC_HISTOGRAM_COUNTS_LINEAR(
+        /*name=*/"WebRTC.Audio.ApmAnalogGainIncreaseAverage",
+        /*sample=*/average_increase,
+        /*min=*/1,
+        /*max=*/kMaxUpdate,
+        /*bucket_count=*/50);
   }
-  metrics::HistogramAdd(update_rate_histogram_, num_updates);
+  RTC_HISTOGRAM_COUNTS_LINEAR(
+      /*name=*/"WebRTC.Audio.ApmAnalogGainUpdateRate",
+      /*sample=*/num_updates,
+      /*min=*/1,
+      /*max=*/kFramesIn60Seconds,
+      /*bucket_count=*/50);
   if (num_updates > 0) {
-    metrics::HistogramAdd(update_average_histogram_, average_update);
+    RTC_HISTOGRAM_COUNTS_LINEAR(
+        /*name=*/"WebRTC.Audio.ApmAnalogGainUpdateAverage",
+        /*sample=*/average_update,
+        /*min=*/1,
+        /*max=*/kMaxUpdate,
+        /*bucket_count=*/50);
   }
 }
 
diff --git a/modules/audio_processing/agc2/input_volume_stats_reporter.h b/modules/audio_processing/agc2/input_volume_stats_reporter.h
index 757e6ff..0040754 100644
--- a/modules/audio_processing/agc2/input_volume_stats_reporter.h
+++ b/modules/audio_processing/agc2/input_volume_stats_reporter.h
@@ -13,7 +13,6 @@
 
 #include "absl/types/optional.h"
 #include "rtc_base/gtest_prod_util.h"
-#include "system_wrappers/include/metrics.h"
 
 namespace webrtc {
 
@@ -22,12 +21,7 @@
 // the statistics into a histogram.
 class InputVolumeStatsReporter {
  public:
-  enum class InputVolumeType {
-    kApplied = 0,
-    kRecommended = 1,
-  };
-
-  explicit InputVolumeStatsReporter(InputVolumeType input_volume_type);
+  InputVolumeStatsReporter();
   InputVolumeStatsReporter(const InputVolumeStatsReporter&) = delete;
   InputVolumeStatsReporter operator=(const InputVolumeStatsReporter&) = delete;
   ~InputVolumeStatsReporter();
@@ -63,14 +57,6 @@
   // Computes aggregate stat and logs them into a histogram.
   void LogVolumeUpdateStats() const;
 
-  // Histograms.
-  metrics::Histogram* decrease_rate_histogram_;
-  metrics::Histogram* decrease_average_histogram_;
-  metrics::Histogram* increase_rate_histogram_;
-  metrics::Histogram* increase_average_histogram_;
-  metrics::Histogram* update_rate_histogram_;
-  metrics::Histogram* update_average_histogram_;
-
   int log_volume_update_stats_counter_ = 0;
   absl::optional<int> previous_input_volume_ = absl::nullopt;
 };
diff --git a/modules/audio_processing/agc2/input_volume_stats_reporter_unittest.cc b/modules/audio_processing/agc2/input_volume_stats_reporter_unittest.cc
index a3e2cca..f8cd010 100644
--- a/modules/audio_processing/agc2/input_volume_stats_reporter_unittest.cc
+++ b/modules/audio_processing/agc2/input_volume_stats_reporter_unittest.cc
@@ -10,71 +10,24 @@
 
 #include "modules/audio_processing/agc2/input_volume_stats_reporter.h"
 
-#include "absl/strings/string_view.h"
-#include "rtc_base/strings/string_builder.h"
 #include "system_wrappers/include/metrics.h"
 #include "test/gmock.h"
 
 namespace webrtc {
 namespace {
 
-using InputVolumeType = InputVolumeStatsReporter::InputVolumeType;
-
 constexpr int kFramesIn60Seconds = 6000;
 
-constexpr absl::string_view kLabelPrefix = "WebRTC.Audio.Apm.";
-
-class InputVolumeStatsReporterTest
-    : public ::testing::TestWithParam<InputVolumeType> {
+class InputVolumeStatsReporterTest : public ::testing::Test {
  public:
-  InputVolumeStatsReporterTest() { metrics::Reset(); }
+  InputVolumeStatsReporterTest() {}
 
  protected:
-  InputVolumeType InputVolumeType() const { return GetParam(); }
-  std::string DecreaseRateLabel() const {
-    return (rtc::StringBuilder(kLabelPrefix)
-            << VolumeTypeLabel() << "DecreaseRate")
-        .str();
-  }
-  std::string DecreaseAverageLabel() const {
-    return (rtc::StringBuilder(kLabelPrefix)
-            << VolumeTypeLabel() << "DecreaseAverage")
-        .str();
-  }
-  std::string IncreaseRateLabel() const {
-    return (rtc::StringBuilder(kLabelPrefix)
-            << VolumeTypeLabel() << "IncreaseRate")
-        .str();
-  }
-  std::string IncreaseAverageLabel() const {
-    return (rtc::StringBuilder(kLabelPrefix)
-            << VolumeTypeLabel() << "IncreaseAverage")
-        .str();
-  }
-  std::string UpdateRateLabel() const {
-    return (rtc::StringBuilder(kLabelPrefix)
-            << VolumeTypeLabel() << "UpdateRate")
-        .str();
-  }
-  std::string UpdateAverageLabel() const {
-    return (rtc::StringBuilder(kLabelPrefix)
-            << VolumeTypeLabel() << "UpdateAverage")
-        .str();
-  }
-
- private:
-  absl::string_view VolumeTypeLabel() const {
-    switch (InputVolumeType()) {
-      case InputVolumeType::kApplied:
-        return "AppliedInputVolume.";
-      case InputVolumeType::kRecommended:
-        return "RecommendedInputVolume.";
-    }
-  }
+  void SetUp() override { metrics::Reset(); }
 };
 
-TEST_P(InputVolumeStatsReporterTest, CheckLogVolumeUpdateStatsEmpty) {
-  InputVolumeStatsReporter stats_reporter(InputVolumeType());
+TEST_F(InputVolumeStatsReporterTest, CheckLogVolumeUpdateStatsEmpty) {
+  InputVolumeStatsReporter stats_reporter;
   constexpr int kInputVolume = 10;
   stats_reporter.UpdateStatistics(kInputVolume);
   // Update almost until the periodic logging and reset.
@@ -82,22 +35,25 @@
     stats_reporter.UpdateStatistics(kInputVolume + 2);
     stats_reporter.UpdateStatistics(kInputVolume);
   }
-  EXPECT_METRIC_THAT(metrics::Samples(UpdateRateLabel()),
+  EXPECT_METRIC_THAT(metrics::Samples("WebRTC.Audio.ApmAnalogGainUpdateRate"),
                      ::testing::ElementsAre());
-  EXPECT_METRIC_THAT(metrics::Samples(DecreaseRateLabel()),
+  EXPECT_METRIC_THAT(metrics::Samples("WebRTC.Audio.ApmAnalogGainDecreaseRate"),
                      ::testing::ElementsAre());
-  EXPECT_METRIC_THAT(metrics::Samples(IncreaseRateLabel()),
+  EXPECT_METRIC_THAT(metrics::Samples("WebRTC.Audio.ApmAnalogGainIncreaseRate"),
                      ::testing::ElementsAre());
-  EXPECT_METRIC_THAT(metrics::Samples(UpdateAverageLabel()),
-                     ::testing::ElementsAre());
-  EXPECT_METRIC_THAT(metrics::Samples(DecreaseAverageLabel()),
-                     ::testing::ElementsAre());
-  EXPECT_METRIC_THAT(metrics::Samples(IncreaseAverageLabel()),
-                     ::testing::ElementsAre());
+  EXPECT_METRIC_THAT(
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainUpdateAverage"),
+      ::testing::ElementsAre());
+  EXPECT_METRIC_THAT(
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainDecreaseAverage"),
+      ::testing::ElementsAre());
+  EXPECT_METRIC_THAT(
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainIncreaseAverage"),
+      ::testing::ElementsAre());
 }
 
-TEST_P(InputVolumeStatsReporterTest, CheckLogVolumeUpdateStatsNotEmpty) {
-  InputVolumeStatsReporter stats_reporter(InputVolumeType());
+TEST_F(InputVolumeStatsReporterTest, CheckLogVolumeUpdateStatsNotEmpty) {
+  InputVolumeStatsReporter stats_reporter;
   constexpr int kInputVolume = 10;
   stats_reporter.UpdateStatistics(kInputVolume);
   // Update until periodic logging.
@@ -111,30 +67,30 @@
     stats_reporter.UpdateStatistics(kInputVolume);
   }
   EXPECT_METRIC_THAT(
-      metrics::Samples(UpdateRateLabel()),
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainUpdateRate"),
       ::testing::ElementsAre(::testing::Pair(kFramesIn60Seconds - 1, 1),
                              ::testing::Pair(kFramesIn60Seconds, 1)));
   EXPECT_METRIC_THAT(
-      metrics::Samples(DecreaseRateLabel()),
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainDecreaseRate"),
       ::testing::ElementsAre(::testing::Pair(kFramesIn60Seconds / 2 - 1, 1),
                              ::testing::Pair(kFramesIn60Seconds / 2, 1)));
   EXPECT_METRIC_THAT(
-      metrics::Samples(IncreaseRateLabel()),
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainIncreaseRate"),
       ::testing::ElementsAre(::testing::Pair(kFramesIn60Seconds / 2, 2)));
   EXPECT_METRIC_THAT(
-      metrics::Samples(UpdateAverageLabel()),
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainUpdateAverage"),
       ::testing::ElementsAre(::testing::Pair(2, 1), ::testing::Pair(3, 1)));
   EXPECT_METRIC_THAT(
-      metrics::Samples(DecreaseAverageLabel()),
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainDecreaseAverage"),
       ::testing::ElementsAre(::testing::Pair(2, 1), ::testing::Pair(3, 1)));
   EXPECT_METRIC_THAT(
-      metrics::Samples(IncreaseAverageLabel()),
+      metrics::Samples("WebRTC.Audio.ApmAnalogGainIncreaseAverage"),
       ::testing::ElementsAre(::testing::Pair(2, 1), ::testing::Pair(3, 1)));
 }
 }  // namespace
 
-TEST_P(InputVolumeStatsReporterTest, CheckVolumeUpdateStatsForEmptyStats) {
-  InputVolumeStatsReporter stats_reporter(InputVolumeType());
+TEST_F(InputVolumeStatsReporterTest, CheckVolumeUpdateStatsForEmptyStats) {
+  InputVolumeStatsReporter stats_reporter;
   const auto& update_stats = stats_reporter.volume_update_stats();
   EXPECT_EQ(update_stats.num_decreases, 0);
   EXPECT_EQ(update_stats.sum_decreases, 0);
@@ -142,10 +98,10 @@
   EXPECT_EQ(update_stats.sum_increases, 0);
 }
 
-TEST_P(InputVolumeStatsReporterTest,
+TEST_F(InputVolumeStatsReporterTest,
        CheckVolumeUpdateStatsAfterNoVolumeChange) {
   constexpr int kInputVolume = 10;
-  InputVolumeStatsReporter stats_reporter(InputVolumeType());
+  InputVolumeStatsReporter stats_reporter;
   stats_reporter.UpdateStatistics(kInputVolume);
   stats_reporter.UpdateStatistics(kInputVolume);
   stats_reporter.UpdateStatistics(kInputVolume);
@@ -156,10 +112,10 @@
   EXPECT_EQ(update_stats.sum_increases, 0);
 }
 
-TEST_P(InputVolumeStatsReporterTest,
+TEST_F(InputVolumeStatsReporterTest,
        CheckVolumeUpdateStatsAfterVolumeIncrease) {
   constexpr int kInputVolume = 10;
-  InputVolumeStatsReporter stats_reporter(InputVolumeType());
+  InputVolumeStatsReporter stats_reporter;
   stats_reporter.UpdateStatistics(kInputVolume);
   stats_reporter.UpdateStatistics(kInputVolume + 4);
   stats_reporter.UpdateStatistics(kInputVolume + 5);
@@ -170,10 +126,10 @@
   EXPECT_EQ(update_stats.sum_increases, 5);
 }
 
-TEST_P(InputVolumeStatsReporterTest,
+TEST_F(InputVolumeStatsReporterTest,
        CheckVolumeUpdateStatsAfterVolumeDecrease) {
   constexpr int kInputVolume = 10;
-  InputVolumeStatsReporter stats_reporter(InputVolumeType());
+  InputVolumeStatsReporter stats_reporter;
   stats_reporter.UpdateStatistics(kInputVolume);
   stats_reporter.UpdateStatistics(kInputVolume - 4);
   stats_reporter.UpdateStatistics(kInputVolume - 5);
@@ -184,8 +140,8 @@
   EXPECT_EQ(stats_update.sum_increases, 0);
 }
 
-TEST_P(InputVolumeStatsReporterTest, CheckVolumeUpdateStatsAfterReset) {
-  InputVolumeStatsReporter stats_reporter(InputVolumeType());
+TEST_F(InputVolumeStatsReporterTest, CheckVolumeUpdateStatsAfterReset) {
+  InputVolumeStatsReporter stats_reporter;
   constexpr int kInputVolume = 10;
   stats_reporter.UpdateStatistics(kInputVolume);
   // Update until the periodic reset.
@@ -213,9 +169,4 @@
   EXPECT_EQ(stats_after_reset.sum_increases, 3);
 }
 
-INSTANTIATE_TEST_SUITE_P(,
-                         InputVolumeStatsReporterTest,
-                         ::testing::Values(InputVolumeType::kApplied,
-                                           InputVolumeType::kRecommended));
-
 }  // namespace webrtc
diff --git a/modules/audio_processing/audio_processing_impl.cc b/modules/audio_processing/audio_processing_impl.cc
index a0415e2..76e3804 100644
--- a/modules/audio_processing/audio_processing_impl.cc
+++ b/modules/audio_processing/audio_processing_impl.cc
@@ -291,11 +291,7 @@
                  MinimizeProcessingForUnusedOutput(),
                  field_trial::IsEnabled("WebRTC-TransientSuppressorForcedOff")),
       capture_(),
-      capture_nonlocked_(),
-      applied_input_volume_stats_reporter_(
-          InputVolumeStatsReporter::InputVolumeType::kApplied),
-      recommended_input_volume_stats_reporter_(
-          InputVolumeStatsReporter::InputVolumeType::kRecommended) {
+      capture_nonlocked_() {
   RTC_LOG(LS_INFO) << "Injected APM submodules:"
                       "\nEcho control factory: "
                    << !!echo_control_factory_
@@ -1365,10 +1361,6 @@
   stats_reporter_.UpdateStatistics(capture_.stats);
 
   UpdateRecommendedInputVolumeLocked();
-  if (capture_.recommended_input_volume.has_value()) {
-    recommended_input_volume_stats_reporter_.UpdateStatistics(
-        *capture_.recommended_input_volume);
-  }
 
   if (submodules_.capture_levels_adjuster) {
     submodules_.capture_levels_adjuster->ApplyPostLevelAdjustment(
diff --git a/modules/audio_processing/audio_processing_impl.h b/modules/audio_processing/audio_processing_impl.h
index 5daea90..bc582b5 100644
--- a/modules/audio_processing/audio_processing_impl.h
+++ b/modules/audio_processing/audio_processing_impl.h
@@ -541,8 +541,6 @@
 
   InputVolumeStatsReporter applied_input_volume_stats_reporter_
       RTC_GUARDED_BY(mutex_capture_);
-  InputVolumeStatsReporter recommended_input_volume_stats_reporter_
-      RTC_GUARDED_BY(mutex_capture_);
 
   // Lock protection not needed.
   std::unique_ptr<