Move the aec_rdft* files to a more proper place beneath APM and make them thread-safe.

webrtc/modules/audio_processing/level_controller/signal_classifier.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_LEVEL_CONTROLLER_SIGNAL_CLASSIFIER_H_
 #define WEBRTC_MODULES_AUDIO_PROCESSING_LEVEL_CONTROLLER_SIGNAL_CLASSIFIER_H_
 
 #include <memory>
 #include <vector>
 
 #include "webrtc/base/array_view.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/modules/audio_processing/level_controller/down_sampler.h"
 #include "webrtc/modules/audio_processing/level_controller/noise_spectrum_estimator.h"
+#include "webrtc/modules/audio_processing/utility/ooura_fft.h"
 
 namespace webrtc {
 
 class ApmDataDumper;
 class AudioBuffer;
 
 class SignalClassifier {
  public:
   enum class SignalType { kHighlyNonStationary, kNonStationary, kStationary };
 
@@ skipping 19 matching lines @@
   };
 
   ApmDataDumper* const data_dumper_;
   DownSampler down_sampler_;
   std::unique_ptr<FrameExtender> frame_extender_;
   NoiseSpectrumEstimator noise_spectrum_estimator_;
   int sample_rate_hz_;
   int initialization_frames_left_;
   int consistent_classification_counter_;
   SignalType last_signal_type_;
+  const OouraFft ooura_fft_;
   RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(SignalClassifier);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_MODULES_AUDIO_PROCESSING_LEVEL_CONTROLLER_SIGNAL_CLASSIFIER_H_