Reland of Added ARM Neon SIMD optimizations for AEC3

webrtc/modules/audio_processing/aec3/aec3_common.h

 /*
  *  Copyright (c) 2016 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.
  */
 
 #ifndef WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC3_COMMON_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC3_COMMON_H_
 
 #include <stddef.h>
 #include "webrtc/typedefs.h"
 
 namespace webrtc {
 
 #ifdef _MSC_VER /* visual c++ */
 #define ALIGN16_BEG __declspec(align(16))
 #define ALIGN16_END
 #else /* gcc or icc */
 #define ALIGN16_BEG
 #define ALIGN16_END __attribute__((aligned(16)))
 #endif
 
-enum class Aec3Optimization { kNone, kSse2 };
+enum class Aec3Optimization { kNone, kSse2, kNeon };
 
 constexpr int kNumBlocksPerSecond = 250;
 
 constexpr int kMetricsReportingIntervalBlocks = 10 * kNumBlocksPerSecond;
 constexpr int kMetricsComputationBlocks = 9;
 constexpr int kMetricsCollectionBlocks =
     kMetricsReportingIntervalBlocks - kMetricsComputationBlocks;
 
 constexpr int kAdaptiveFilterLength = 12;
 constexpr int kResidualEchoPowerRenderWindowSize = 30;
@@ skipping 67 matching lines @@
 static_assert(ValidFullBandRate(32000),
               "Test that 32 kHz is a valid sample rate");
 static_assert(ValidFullBandRate(48000),
               "Test that 48 kHz is a valid sample rate");
 static_assert(!ValidFullBandRate(8001),
               "Test that 8001 Hz is not a valid sample rate");
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_AEC3_AEC3_COMMON_H_