Add empty residual echo detector.

webrtc/modules/audio_processing/echo_detector/echo_detector.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_ECHO_DETECTOR_ECHO_DETECTOR_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_ECHO_DETECTOR_ECHO_DETECTOR_H_
+
 #include <stddef.h>
-#include <stdint.h>
-
-#include "webrtc/api/jsepsessiondescription.h"
 
 namespace webrtc {
-void FuzzOneInput(const uint8_t* data, size_t size) {
-  std::string message(reinterpret_cast<const char*>(data), size);
-  webrtc::SdpParseError error;
 
-  std::unique_ptr<webrtc::SessionDescriptionInterface> sdp(
-      CreateSessionDescription("offer", message, &error));
-}
+class EchoDetector {
+ public:
+  EchoDetector() {}
+  ~EchoDetector() {}
+
+  void BufferFarend(const float* farend, size_t num_samples);

[hlundin-webrtc, 2016/10/14 07:15:52]

I think you should use rtc::ArrayView<const float> instead of "const float*
farend, size_t num_samples".

[kwiberg-webrtc, 2016/10/14 07:28:48]

+1. ArrayView should be used instead of separate pointer+size pretty much
everywhere.

[ivoc, 2016/10/14 09:53:19]

Done.

+
+  void Process(const float* nearend, size_t num_samples);

[hlundin-webrtc, 2016/10/14 07:15:53]

And here.

[ivoc, 2016/10/14 09:53:18]

Done.

+
+  void Initialize(int sample_rate_hz);
+};
 
 }  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_ECHO_DETECTOR_ECHO_DETECTOR_H_