Adding second layer of the echo canceller 3 functionality.

webrtc/modules/BUILD.gn

Index: webrtc/modules/BUILD.gn
diff --git a/webrtc/modules/BUILD.gn b/webrtc/modules/BUILD.gn
index cfe12845bf9739fbaa623a85aa25e936522880a2..266a9ee28ffc969b04575ab37fe62259a353bfa3 100644
--- a/webrtc/modules/BUILD.gn
+++ b/webrtc/modules/BUILD.gn
@@ -601,8 +601,15 @@ if (rtc_include_tests) {
         "audio_processing/aec3/block_processor_unittest.cc",
         "audio_processing/aec3/cascaded_biquad_filter_unittest.cc",
         "audio_processing/aec3/echo_canceller3_unittest.cc",
+        "audio_processing/aec3/echo_path_delay_estimator_unittest.cc",
+        "audio_processing/aec3/echo_remover_unittest.cc",
         "audio_processing/aec3/frame_blocker_unittest.cc",
         "audio_processing/aec3/mock/mock_block_processor.h",
+        "audio_processing/aec3/mock/mock_echo_remover.h",
+        "audio_processing/aec3/mock/mock_render_delay_buffer.h",
+        "audio_processing/aec3/mock/mock_render_delay_controller.h",
+        "audio_processing/aec3/render_delay_buffer_unittest.cc",
+        "audio_processing/aec3/render_delay_controller_unittest.cc",
         "audio_processing/audio_processing_impl_locking_unittest.cc",
         "audio_processing/audio_processing_impl_unittest.cc",
         "audio_processing/audio_processing_unittest.cc",
@@ -623,6 +630,9 @@ if (rtc_include_tests) {
         "audio_processing/test/debug_dump_replayer.cc",
         "audio_processing/test/debug_dump_replayer.h",
         "audio_processing/test/debug_dump_test.cc",
+        "audio_processing/test/echo_canceller_test_tools.cc",
+        "audio_processing/test/echo_canceller_test_tools.h",
+        "audio_processing/test/echo_canceller_test_tools_unittest.cc",
         "audio_processing/test/test_utils.h",
         "audio_processing/voice_detection_unittest.cc",
       ]