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>

[ivoc, 2016/10/12 15:40:13]

It seems like the diff has chosen another random file as a base here. Please
ignore this, this is a newly created file.

-
-#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 {

[peah-webrtc, 2016/10/13 10:11:17]

What is the difference between the EchoDetector and ResidualEchoDetector
classes?

[ivoc, 2016/10/13 10:31:25]

I was planning to put the actual algorithmic code in here, and use the
ResidualEchoDetector as a wrapper to integrate it into APM. Of course it's
possible to do both of these from a single class, do you think that would be
better?

[peah-webrtc, 2016/10/13 10:50:27]

That sounds good! It is very hard to tell at this stage. You know the better
than me as you know what follows. 

+ public:
+  EchoDetector() {}
+  ~EchoDetector() {}
+
+  void BufferFarend(const float* farend, size_t nrOfSamples);
+
+  void Process(const float* nearend, size_t nrOfSamples);
+
+  void Initialize(int sample_rate_hz);
+};
 
 }  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_ECHO_DETECTOR_ECHO_DETECTOR_H_