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/vad/pitch_internal.h

@@ -0,0 +1,26 @@
+/*
+ *  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_VAD_PITCH_INTERNAL_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_VAD_PITCH_INTERNAL_H_
+
+// TODO(turajs): Write a description of this function. Also be consistent with
+// usage of |sampling_rate_hz| vs |kSamplingFreqHz|.
+void GetSubframesPitchParameters(int sampling_rate_hz,
+                                 double* gains,
+                                 double* lags,
+                                 int num_in_frames,
+                                 int num_out_frames,
+                                 double* log_old_gain,
+                                 double* old_lag,
+                                 double* log_pitch_gain,
+                                 double* pitch_lag_hz);
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_VAD_PITCH_INTERNAL_H_