Added ARM Neon SIMD optimizations for AEC3

webrtc/modules/audio_processing/aec3/aec3_common.cc

 /*
  *  Copyright (c) 2017 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.
  */
 
 #include "webrtc/modules/audio_processing/aec3/aec3_common.h"
 
 #include "webrtc/typedefs.h"
 #include "webrtc/system_wrappers/include/cpu_features_wrapper.h"
 
 namespace webrtc {
 
 Aec3Optimization DetectOptimization() {
 #if defined(WEBRTC_ARCH_X86_FAMILY)
   if (WebRtc_GetCPUInfo(kSSE2) != 0) {
     return Aec3Optimization::kSse2;
   }
 #endif
+
+#if defined(WEBRTC_HAS_NEON)
+  return Aec3Optimization::kNeon;
+#endif
+
   return Aec3Optimization::kNone;
 }
 
 }  // namespace webrtc