Add algorithm for Residual Echo Detector.

webrtc/modules/audio_processing/audio_processing.gypi

 # 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.
 
 {
   'variables': {
@@ skipping 55 matching lines @@
         'beamformer/covariance_matrix_generator.cc',
         'beamformer/covariance_matrix_generator.h',
         'beamformer/matrix.h',
         'beamformer/nonlinear_beamformer.cc',
         'beamformer/nonlinear_beamformer.h',
         'common.h',
         'echo_cancellation_impl.cc',
         'echo_cancellation_impl.h',
         'echo_control_mobile_impl.cc',
         'echo_control_mobile_impl.h',
+        'echo_detector/circular_buffer.cc',
+        'echo_detector/circular_buffer.h',
+        'echo_detector/mean_variance_estimator.cc',
+        'echo_detector/mean_variance_estimator.h',
+        'echo_detector/normalized_covariance_estimator.cc',
+        'echo_detector/normalized_covariance_estimator.h',
         'gain_control_for_experimental_agc.cc',
         'gain_control_for_experimental_agc.h',
         'gain_control_impl.cc',
         'gain_control_impl.h',
         'high_pass_filter_impl.cc',
         'high_pass_filter_impl.h',
         'include/audio_processing.cc',
         'include/audio_processing.h',
         'include/config.cc',
         'include/config.h',
@@ skipping 231 matching lines @@
             'defines': ['WEBRTC_APM_DEBUG_DUMP=1',],
           }],
           ['apm_debug_dump==0', {
             'defines': ['WEBRTC_APM_DEBUG_DUMP=0',],
           }],
         ],
       }],
     }],
   ],
 }