Add empty residual echo detector.

webrtc/modules/audio_processing/residual_echo_detector.h

Index: webrtc/modules/audio_processing/residual_echo_detector.h
diff --git a/webrtc/modules/audio_processing/residual_echo_detector.h b/webrtc/modules/audio_processing/residual_echo_detector.h
new file mode 100644
index 0000000000000000000000000000000000000000..d87e77f850737a600111d4fb3343ce358751e341
--- /dev/null
+++ b/webrtc/modules/audio_processing/residual_echo_detector.h
@@ -0,0 +1,64 @@
+/*
+ *  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_RESIDUAL_ECHO_DETECTOR_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_RESIDUAL_ECHO_DETECTOR_H_
+
+#include <memory>
+#include <vector>
+
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/criticalsection.h"
+#include "webrtc/base/optional.h"
+#include "webrtc/base/swap_queue.h"
+#include "webrtc/modules/audio_processing/include/audio_processing.h"
+#include "webrtc/modules/audio_processing/render_queue_item_verifier.h"
+
+namespace webrtc {
+
+class AudioBuffer;
+class EchoDetector;
+
+class ResidualEchoDetector {
+ public:
+  ResidualEchoDetector(rtc::CriticalSection* crit_render,
+                       rtc::CriticalSection* crit_capture);
+  ~ResidualEchoDetector();
+
+  void AnalyzeRenderAudio(const AudioBuffer* audio);
+  void AnalyzeCaptureAudio(AudioBuffer* audio);
+
+  void Initialize(int sample_rate_hz);
+
+  // Reads render side data that has been queued on the render call.
+  // Called holding the capture lock.
+  void ReadQueuedRenderData();
+
+  float get_echo_likelihood();
+
+ private:
+  rtc::CriticalSection* const crit_render_ ACQUIRED_BEFORE(crit_capture_);
+  rtc::CriticalSection* const crit_capture_;
+
+  std::vector<float> render_queue_buffer_ GUARDED_BY(crit_render_);
+  std::vector<float> capture_queue_buffer_ GUARDED_BY(crit_capture_);
+
+  // Lock protection not needed.
+  std::unique_ptr<SwapQueue<std::vector<float>, RenderQueueItemVerifier<float>>>
+      render_signal_queue_;
+
+  std::unique_ptr<EchoDetector> detector_;
+
+  RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(ResidualEchoDetector);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_RESIDUAL_ECHO_DETECTOR_H_