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_tree.cc

@@ -0,0 +1,119 @@
+/*
+ *  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_tree.h"
+
+#include <assert.h>
+#include <math.h>
+#include <string.h>
+
+#include "webrtc/base/scoped_ptr.h"
+#include "webrtc/modules/audio_processing/transient/dyadic_decimator.h"
+#include "webrtc/modules/audio_processing/transient/wpd_node.h"
+
+namespace webrtc {
+
+WPDTree::WPDTree(size_t data_length, const float* high_pass_coefficients,
+                 const float* low_pass_coefficients, size_t coefficients_length,
+                 int levels)
+    : data_length_(data_length),
+      levels_(levels),
+      num_nodes_((1 << (levels + 1)) - 1) {
+  assert(data_length > (static_cast<size_t>(1) << levels) &&
+         high_pass_coefficients &&
+         low_pass_coefficients &&
+         levels > 0);
+  // Size is 1 more, so we can use the array as 1-based. nodes_[0] is never
+  // allocated.
+  nodes_.reset(new rtc::scoped_ptr<WPDNode>[num_nodes_ + 1]);
+
+  // Create the first node
+  const float kRootCoefficient = 1.f;  // Identity Coefficient.
+  nodes_[1].reset(new WPDNode(data_length, &kRootCoefficient, 1));
+  // Variables used to create the rest of the nodes.
+  size_t index = 1;
+  size_t index_left_child = 0;
+  size_t index_right_child = 0;
+
+  int num_nodes_at_curr_level = 0;
+
+  // Branching each node in each level to create its children. The last level is
+  // not branched (all the nodes of that level are leaves).
+  for (int current_level = 0; current_level < levels; ++current_level) {
+    num_nodes_at_curr_level = 1 << current_level;
+    for (int i = 0; i < num_nodes_at_curr_level; ++i) {
+      index = (1 << current_level) + i;
+      // Obtain the index of the current node children.
+      index_left_child = index * 2;
+      index_right_child = index_left_child + 1;
+      nodes_[index_left_child].reset(new WPDNode(nodes_[index]->length() / 2,
+                                                 low_pass_coefficients,
+                                                 coefficients_length));
+      nodes_[index_right_child].reset(new WPDNode(nodes_[index]->length() / 2,
+                                                  high_pass_coefficients,
+                                                  coefficients_length));
+    }
+  }
+}
+
+WPDTree::~WPDTree() {}
+
+WPDNode* WPDTree::NodeAt(int level, int index) {
+  const int kNumNodesAtLevel = 1 << level;
+  if (level < 0 || level > levels_ || index < 0 || index >= kNumNodesAtLevel) {
+    return NULL;
+  }
+  return nodes_[(1 << level) + index].get();
+}
+
+int WPDTree::Update(const float* data, size_t data_length) {
+  if (!data || data_length != data_length_) {
+    return -1;
+  }
+
+  // Update the root node.
+  int update_result = nodes_[1]->set_data(data, data_length);
+  if (update_result != 0) {
+    return -1;
+  }
+
+  // Variables used to update the rest of the nodes.
+  size_t index = 1;
+  size_t index_left_child = 0;
+  size_t index_right_child = 0;
+
+  int num_nodes_at_curr_level = 0;
+
+  for (int current_level = 0; current_level < levels_; ++current_level) {
+    num_nodes_at_curr_level = 1 << current_level;
+    for (int i = 0; i < num_nodes_at_curr_level; ++i) {
+      index = (1 << current_level) + i;
+      // Obtain the index of the current node children.
+      index_left_child = index * 2;
+      index_right_child = index_left_child + 1;
+
+      update_result = nodes_[index_left_child]->Update(
+          nodes_[index]->data(), nodes_[index]->length());
+      if (update_result != 0) {
+        return -1;
+      }
+
+      update_result = nodes_[index_right_child]->Update(
+          nodes_[index]->data(), nodes_[index]->length());
+      if (update_result != 0) {
+        return -1;
+      }
+    }
+  }
+
+  return 0;
+}
+
+}  // namespace webrtc