Revert of Moved the ringbuffer to be built using C++

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 103 matching lines @@
     "utility/block_mean_calculator.h",
     "utility/blocker.cc",
     "utility/blocker.h",
     "utility/delay_estimator.c",
     "utility/delay_estimator.h",
     "utility/delay_estimator_internal.h",
     "utility/delay_estimator_wrapper.c",
     "utility/delay_estimator_wrapper.h",
     "utility/lapped_transform.cc",
     "utility/lapped_transform.h",
-    "utility/ring_buffer.cc",
+    "utility/ring_buffer.c",
     "utility/ring_buffer.h",
     "vad/common.h",
     "vad/gmm.cc",
     "vad/gmm.h",
     "vad/noise_gmm_tables.h",
     "vad/pitch_based_vad.cc",
     "vad/pitch_based_vad.h",
     "vad/pitch_internal.cc",
     "vad/pitch_internal.h",
     "vad/pole_zero_filter.cc",
@@ skipping 153 matching lines @@
     }
 
     configs += [ "../..:common_config" ]
     public_configs = [ "../..:common_inherited_config" ]
 
     deps = [
       "../../common_audio",
     ]
   }
 }