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/transient/wpd_node.cc

@@ -0,0 +1,71 @@
+/*
+ *  Copyright (c) 2013 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.
+ */
+
+#include "webrtc/modules/audio_processing/transient/wpd_node.h"
+
+#include <assert.h>
+#include <math.h>
+#include <string.h>
+
+#include "webrtc/base/scoped_ptr.h"
+#include "webrtc/common_audio/fir_filter.h"
+#include "webrtc/modules/audio_processing/transient/dyadic_decimator.h"
+
+namespace webrtc {
+
+WPDNode::WPDNode(size_t length,
+                 const float* coefficients,
+                 size_t coefficients_length)
+    : // The data buffer has parent data length to be able to contain and filter
+      // it.
+      data_(new float[2 * length + 1]),
+      length_(length),
+      filter_(FIRFilter::Create(coefficients,
+                                coefficients_length,
+                                2 * length + 1)) {
+  assert(length > 0 && coefficients && coefficients_length > 0);
+  memset(data_.get(), 0.f, (2 * length + 1) * sizeof(data_[0]));
+}
+
+WPDNode::~WPDNode() {}
+
+int WPDNode::Update(const float* parent_data, size_t parent_data_length) {
+  if (!parent_data || (parent_data_length / 2) != length_) {
+    return -1;
+  }
+
+  // Filter data.
+  filter_->Filter(parent_data, parent_data_length, data_.get());
+
+  // Decimate data.
+  const bool kOddSequence = true;
+  size_t output_samples = DyadicDecimate(
+      data_.get(), parent_data_length, kOddSequence, data_.get(), length_);
+  if (output_samples != length_) {
+    return -1;
+  }
+
+  // Get abs to all values.
+  for (size_t i = 0; i < length_; ++i) {
+    data_[i] = fabs(data_[i]);
+  }
+
+  return 0;
+}
+
+int WPDNode::set_data(const float* new_data, size_t length) {
+  if (!new_data || length != length_) {
+    return -1;
+  }
+  memcpy(data_.get(), new_data, length * sizeof(data_[0]));
+  return 0;
+}
+
+}  // namespace webrtc