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/utility/delay_estimator_internal.h

@@ -0,0 +1,48 @@
+/*
+ *  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.
+ */
+
+// Header file including the delay estimator handle used for testing.
+
+#ifndef WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_DELAY_ESTIMATOR_INTERNAL_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_DELAY_ESTIMATOR_INTERNAL_H_
+
+#include "webrtc/modules/audio_processing/utility/delay_estimator.h"
+#include "webrtc/typedefs.h"
+
+typedef union {
+  float float_;
+  int32_t int32_;
+} SpectrumType;
+
+typedef struct {
+  // Pointers to mean values of spectrum.
+  SpectrumType* mean_far_spectrum;
+  // |mean_far_spectrum| initialization indicator.
+  int far_spectrum_initialized;
+
+  int spectrum_size;
+
+  // Far-end part of binary spectrum based delay estimation.
+  BinaryDelayEstimatorFarend* binary_farend;
+} DelayEstimatorFarend;
+
+typedef struct {
+  // Pointers to mean values of spectrum.
+  SpectrumType* mean_near_spectrum;
+  // |mean_near_spectrum| initialization indicator.
+  int near_spectrum_initialized;
+
+  int spectrum_size;
+
+  // Binary spectrum based delay estimator
+  BinaryDelayEstimator* binary_handle;
+} DelayEstimator;
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_UTILITY_DELAY_ESTIMATOR_INTERNAL_H_