Major AEC3 render pipeline changes

webrtc/modules/audio_processing/BUILD.gn

Index: webrtc/modules/audio_processing/BUILD.gn
diff --git a/webrtc/modules/audio_processing/BUILD.gn b/webrtc/modules/audio_processing/BUILD.gn
index 36f55756f825fe0b719d6a6c0d0ca1563ade5c65..053bf1d450a636cafb2fd109da32109b55890e98 100644
--- a/webrtc/modules/audio_processing/BUILD.gn
+++ b/webrtc/modules/audio_processing/BUILD.gn
@@ -46,6 +46,8 @@ rtc_static_library("audio_processing") {
     "aec3/comfort_noise_generator.h",
     "aec3/decimator_by_4.cc",
     "aec3/decimator_by_4.h",
+    "aec3/downsampled_render_buffer.cc",
+    "aec3/downsampled_render_buffer.h",
     "aec3/echo_canceller3.cc",
     "aec3/echo_canceller3.h",
     "aec3/echo_path_delay_estimator.cc",
@@ -60,8 +62,6 @@ rtc_static_library("audio_processing") {
     "aec3/erl_estimator.h",
     "aec3/erle_estimator.cc",
     "aec3/erle_estimator.h",
-    "aec3/fft_buffer.cc",
-    "aec3/fft_buffer.h",
     "aec3/fft_data.h",
     "aec3/frame_blocker.cc",
     "aec3/frame_blocker.h",
@@ -75,6 +75,8 @@ rtc_static_library("audio_processing") {
     "aec3/output_selector.h",
     "aec3/power_echo_model.cc",
     "aec3/power_echo_model.h",
+    "aec3/render_buffer.cc",
+    "aec3/render_buffer.h",
     "aec3/render_delay_buffer.cc",
     "aec3/render_delay_buffer.h",
     "aec3/render_delay_controller.cc",
@@ -583,7 +585,6 @@ if (rtc_include_tests) {
         "aec3/echo_remover_unittest.cc",
         "aec3/erl_estimator_unittest.cc",
         "aec3/erle_estimator_unittest.cc",
-        "aec3/fft_buffer_unittest.cc",
         "aec3/fft_data_unittest.cc",
         "aec3/frame_blocker_unittest.cc",
         "aec3/main_filter_update_gain_unittest.cc",
@@ -591,6 +592,7 @@ if (rtc_include_tests) {
         "aec3/matched_filter_unittest.cc",
         "aec3/output_selector_unittest.cc",
         "aec3/power_echo_model_unittest.cc",
+        "aec3/render_buffer_unittest.cc",
         "aec3/render_delay_buffer_unittest.cc",
         "aec3/render_delay_controller_metrics_unittest.cc",
         "aec3/render_delay_controller_unittest.cc",