Major updates to the echo removal functionality in AEC3

webrtc/modules/audio_processing/aec3/render_delay_controller.cc

 /*
  *  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/aec3/render_delay_controller.h"
@@ skipping 92 matching lines @@
 
   ++align_call_counter_;
   rtc::Optional<size_t> echo_path_delay_samples =
       delay_estimator_.EstimateDelay(render_buffer, capture);
   if (echo_path_delay_samples) {
     echo_path_delay_samples_ = *echo_path_delay_samples;
 
     // Compute and set new render delay buffer delay.
     const size_t new_delay =
         ComputeNewBufferDelay(delay_, echo_path_delay_samples_);
-    if (new_delay != delay_ && align_call_counter_ > 250) {
+    if (new_delay != delay_ && align_call_counter_ > kNumBlocksPerSecond) {
       delay_ = new_delay;
     }
 
     // Update render delay buffer headroom.
     blocks_since_last_delay_estimate_ = 0;
     const int headroom = echo_path_delay_samples_ - delay_ * kBlockSize;
     RTC_DCHECK_LE(0, headroom);
     headroom_samples_ = rtc::Optional<size_t>(headroom);
-  } else if (++blocks_since_last_delay_estimate_ > 250 * 20) {
+  } else if (++blocks_since_last_delay_estimate_ > 20 * kNumBlocksPerSecond) {
     headroom_samples_ = rtc::Optional<size_t>();
   }
 
   metrics_.Update(echo_path_delay_samples, delay_);
 
   data_dumper_->DumpRaw("aec3_render_delay_controller_delay", 1,
                         &echo_path_delay_samples_);
   data_dumper_->DumpRaw("aec3_render_delay_controller_buffer_delay", delay_);
 
   return delay_;
 }
 
 }  // namespace
 
 RenderDelayController* RenderDelayController::Create(int sample_rate_hz) {
   return new RenderDelayControllerImpl(sample_rate_hz);
 }
 
 }  // namespace webrtc