Update audio_processing module

Corresponds to upstream commit 524e9b043e7e86fd72353b987c9d5f6a1ebf83e1

Update notes:

 * Pull in third party license file

 * Replace .gypi files with BUILD.gn to keep track of what changes
   upstream

 * Bunch of new filse pulled in as dependencies

 * Won't build yet due to changes needed on top of these

webrtc/modules/audio_processing/ns/include/noise_suppression.h

@@ -0,0 +1,116 @@
+/*
+ *  Copyright (c) 2012 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_NS_INCLUDE_NOISE_SUPPRESSION_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_NS_INCLUDE_NOISE_SUPPRESSION_H_
+
+#include <stddef.h>
+
+#include "webrtc/typedefs.h"
+
+typedef struct NsHandleT NsHandle;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * This function creates an instance of the floating point Noise Suppression.
+ */
+NsHandle* WebRtcNs_Create();
+
+/*
+ * This function frees the dynamic memory of a specified noise suppression
+ * instance.
+ *
+ * Input:
+ *      - NS_inst       : Pointer to NS instance that should be freed
+ */
+void WebRtcNs_Free(NsHandle* NS_inst);
+
+/*
+ * This function initializes a NS instance and has to be called before any other
+ * processing is made.
+ *
+ * Input:
+ *      - NS_inst       : Instance that should be initialized
+ *      - fs            : sampling frequency
+ *
+ * Output:
+ *      - NS_inst       : Initialized instance
+ *
+ * Return value         :  0 - Ok
+ *                        -1 - Error
+ */
+int WebRtcNs_Init(NsHandle* NS_inst, uint32_t fs);
+
+/*
+ * This changes the aggressiveness of the noise suppression method.
+ *
+ * Input:
+ *      - NS_inst       : Noise suppression instance.
+ *      - mode          : 0: Mild, 1: Medium , 2: Aggressive
+ *
+ * Output:
+ *      - NS_inst       : Updated instance.
+ *
+ * Return value         :  0 - Ok
+ *                        -1 - Error
+ */
+int WebRtcNs_set_policy(NsHandle* NS_inst, int mode);
+
+/*
+ * This functions estimates the background noise for the inserted speech frame.
+ * The input and output signals should always be 10ms (80 or 160 samples).
+ *
+ * Input
+ *      - NS_inst       : Noise suppression instance.
+ *      - spframe       : Pointer to speech frame buffer for L band
+ *
+ * Output:
+ *      - NS_inst       : Updated NS instance
+ */
+void WebRtcNs_Analyze(NsHandle* NS_inst, const float* spframe);
+
+/*
+ * This functions does Noise Suppression for the inserted speech frame. The
+ * input and output signals should always be 10ms (80 or 160 samples).
+ *
+ * Input
+ *      - NS_inst       : Noise suppression instance.
+ *      - spframe       : Pointer to speech frame buffer for each band
+ *      - num_bands     : Number of bands
+ *
+ * Output:
+ *      - NS_inst       : Updated NS instance
+ *      - outframe      : Pointer to output frame for each band
+ */
+void WebRtcNs_Process(NsHandle* NS_inst,
+                     const float* const* spframe,
+                     size_t num_bands,
+                     float* const* outframe);
+
+/* Returns the internally used prior speech probability of the current frame.
+ * There is a frequency bin based one as well, with which this should not be
+ * confused.
+ *
+ * Input
+ *      - handle        : Noise suppression instance.
+ *
+ * Return value         : Prior speech probability in interval [0.0, 1.0].
+ *                        -1 - NULL pointer or uninitialized instance.
+ */
+float WebRtcNs_prior_speech_probability(NsHandle* handle);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_NS_INCLUDE_NOISE_SUPPRESSION_H_