Major updates to the echo removal functionality in AEC3

webrtc/modules/audio_processing/aec3/aec3_common.h

Index: webrtc/modules/audio_processing/aec3/aec3_common.h
diff --git a/webrtc/modules/audio_processing/aec3/aec3_common.h b/webrtc/modules/audio_processing/aec3/aec3_common.h
index 480f12c66836256ecb19593a6a0b2c961a6c1aa7..ef7dcdf261bdeefd7d13a66794ece7cadfa1f6f2 100644
--- a/webrtc/modules/audio_processing/aec3/aec3_common.h
+++ b/webrtc/modules/audio_processing/aec3/aec3_common.h
@@ -26,12 +26,15 @@ namespace webrtc {
 
 enum class Aec3Optimization { kNone, kSse2 };
 
-constexpr int kMetricsReportingIntervalBlocks = 10 * 250;
+constexpr int kNumBlocksPerSecond = 250;
+
+constexpr int kMetricsReportingIntervalBlocks = 10 * kNumBlocksPerSecond;
 constexpr int kMetricsComputationBlocks = 9;
 constexpr int kMetricsCollectionBlocks =
     kMetricsReportingIntervalBlocks - kMetricsComputationBlocks;
 
 constexpr int kAdaptiveFilterLength = 12;
+constexpr int kResidualEchoPowerRenderWindowSize = 30;
 
 constexpr size_t kFftLengthBy2 = 64;
 constexpr size_t kFftLengthBy2Plus1 = kFftLengthBy2 + 1;
@@ -55,11 +58,15 @@ constexpr size_t kDownsampledRenderBufferSize =
      kMatchedFilterWindowSizeSubBlocks +
      1);
 
+constexpr float kFixedEchoPathGain = 100;
+
 constexpr size_t kRenderDelayBufferSize =
     (3 * kDownsampledRenderBufferSize) / (4 * kSubBlockSize);
 
 constexpr size_t kMaxApiCallsJitterBlocks = 10;
 constexpr size_t kRenderTransferQueueSize = kMaxApiCallsJitterBlocks / 2;
+static_assert(2 * kRenderTransferQueueSize >= kMaxApiCallsJitterBlocks,
+              "Requirement to ensure buffer overflow detection");
 
 constexpr size_t NumBandsForRate(int sample_rate_hz) {
   return static_cast<size_t>(sample_rate_hz == 8000 ? 1