Pull out the PostFilter to its own NonlinearBeamformer API

webrtc/modules/audio_processing/audio_processing_impl.cc

 /*
  *  Copyright (c) 2012 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.
  */
 
@@ skipping 664 matching lines @@
         capture_nonlocked_.fwd_proc_format.num_frames());
   }
 
   if (fwd_analysis_needed()) {
     ca->SplitIntoFrequencyBands();
   }
 
   if (capture_nonlocked_.beamformer_enabled) {
     private_submodules_->beamformer->ProcessChunk(*ca->split_data_f(),
                                                   ca->split_data_f());
+    // Discards all channels by the leftmost one.
     ca->set_num_channels(1);
   }
 
   public_submodules_->high_pass_filter->ProcessCaptureAudio(ca);
   RETURN_ON_ERR(public_submodules_->gain_control->AnalyzeCaptureAudio(ca));
   public_submodules_->noise_suppression->AnalyzeCaptureAudio(ca);
 
   // Ensure that the stream delay was set before the call to the
   // AEC ProcessCaptureAudio function.
   if (public_submodules_->echo_cancellation->is_enabled() &&
@@ skipping 20 matching lines @@
   // Ensure that the stream delay was set before the call to the
   // AECM ProcessCaptureAudio function.
   if (public_submodules_->echo_control_mobile->is_enabled() &&
       !was_stream_delay_set()) {
     return AudioProcessing::kStreamParameterNotSetError;
   }
 
   RETURN_ON_ERR(public_submodules_->echo_control_mobile->ProcessCaptureAudio(
       ca, stream_delay_ms()));
 
+  if (capture_nonlocked_.beamformer_enabled) {
+    private_submodules_->beamformer->PostFilter(ca->split_data_f());
+  }
+
   public_submodules_->voice_detection->ProcessCaptureAudio(ca);
 
   if (constants_.use_experimental_agc &&
       public_submodules_->gain_control->is_enabled() &&
       (!capture_nonlocked_.beamformer_enabled ||
        private_submodules_->beamformer->is_target_present())) {
     private_submodules_->agc_manager->Process(
         ca->split_bands_const(0)[kBand0To8kHz], ca->num_frames_per_band(),
         capture_nonlocked_.split_rate);
   }
@@ skipping 726 matching lines @@
   debug_dump_.capture.event_msg->mutable_config()->CopyFrom(config);
 
   RETURN_ON_ERR(WriteMessageToDebugFile(debug_dump_.debug_file.get(),
                                         &debug_dump_.num_bytes_left_for_log_,
                                         &crit_debug_, &debug_dump_.capture));
   return kNoError;
 }
 #endif  // WEBRTC_AUDIOPROC_DEBUG_DUMP
 
 }  // namespace webrtc