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/voice_activity_detector.h

@@ -0,0 +1,70 @@
+/*
+ *  Copyright (c) 2015 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_VOICE_ACTIVITY_DETECTOR_H_
+#define WEBRTC_MODULES_AUDIO_PROCESSING_VAD_VOICE_ACTIVITY_DETECTOR_H_
+
+#include <vector>
+
+#include "webrtc/base/scoped_ptr.h"
+#include "webrtc/common_audio/resampler/include/resampler.h"
+#include "webrtc/modules/audio_processing/vad/vad_audio_proc.h"
+#include "webrtc/modules/audio_processing/vad/common.h"
+#include "webrtc/modules/audio_processing/vad/pitch_based_vad.h"
+#include "webrtc/modules/audio_processing/vad/standalone_vad.h"
+
+namespace webrtc {
+
+// A Voice Activity Detector (VAD) that combines the voice probability from the
+// StandaloneVad and PitchBasedVad to get a more robust estimation.
+class VoiceActivityDetector {
+ public:
+  VoiceActivityDetector();
+
+  // Processes each audio chunk and estimates the voice probability. The maximum
+  // supported sample rate is 32kHz.
+  // TODO(aluebs): Change |length| to size_t.
+  void ProcessChunk(const int16_t* audio, size_t length, int sample_rate_hz);
+
+  // Returns a vector of voice probabilities for each chunk. It can be empty for
+  // some chunks, but it catches up afterwards returning multiple values at
+  // once.
+  const std::vector<double>& chunkwise_voice_probabilities() const {
+    return chunkwise_voice_probabilities_;
+  }
+
+  // Returns a vector of RMS values for each chunk. It has the same length as
+  // chunkwise_voice_probabilities().
+  const std::vector<double>& chunkwise_rms() const { return chunkwise_rms_; }
+
+  // Returns the last voice probability, regardless of the internal
+  // implementation, although it has a few chunks of delay.
+  float last_voice_probability() const { return last_voice_probability_; }
+
+ private:
+  // TODO(aluebs): Change these to float.
+  std::vector<double> chunkwise_voice_probabilities_;
+  std::vector<double> chunkwise_rms_;
+
+  float last_voice_probability_;
+
+  Resampler resampler_;
+  VadAudioProc audio_processing_;
+
+  rtc::scoped_ptr<StandaloneVad> standalone_vad_;
+  PitchBasedVad pitch_based_vad_;
+
+  int16_t resampled_[kLength10Ms];
+  AudioFeatures features_;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_AUDIO_PROCESSING_VAD_VOICE_ACTIVITY_DETECTOR_H_