Adding full initial version of delay estimation functionality in echo canceller 3

webrtc/modules/audio_processing/BUILD.gn

 # Copyright (c) 2014 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.
 
 import("//build/config/arm.gni")
 import("//third_party/protobuf/proto_library.gni")
@@ skipping 15 matching lines @@
     "aec/aec_resampler.h",
     "aec/echo_cancellation.cc",
     "aec/echo_cancellation.h",
     "aec3/aec3_constants.h",
     "aec3/block_framer.cc",
     "aec3/block_framer.h",
     "aec3/block_processor.cc",
     "aec3/block_processor.h",
     "aec3/cascaded_biquad_filter.cc",
     "aec3/cascaded_biquad_filter.h",
+    "aec3/correlator.cc",
+    "aec3/correlator.h",
+    "aec3/correlator_lag_aggregator.cc",
+    "aec3/correlator_lag_aggregator.h",
+    "aec3/down_sampler_4khz.cc",
+    "aec3/down_sampler_4khz.h",
     "aec3/echo_canceller3.cc",
     "aec3/echo_canceller3.h",
     "aec3/echo_path_delay_estimator.cc",
     "aec3/echo_path_delay_estimator.h",
     "aec3/echo_path_variability.h",
     "aec3/echo_remover.cc",
     "aec3/echo_remover.h",
     "aec3/frame_blocker.cc",
     "aec3/frame_blocker.h",
     "aec3/render_delay_buffer.cc",
@@ skipping 557 matching lines @@
       ]
 
       deps = [
         ":audioproc_debug_proto",
         "../..:webrtc_common",
         "../../base:rtc_base_approved",
       ]
     }
   }
 }