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/common_audio/wav_header.h

@@ -0,0 +1,64 @@
+/*
+ *  Copyright (c) 2014 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_COMMON_AUDIO_WAV_HEADER_H_
+#define WEBRTC_COMMON_AUDIO_WAV_HEADER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+
+namespace webrtc {
+
+static const size_t kWavHeaderSize = 44;
+
+class ReadableWav {
+ public:
+  // Returns the number of bytes read.
+  size_t virtual Read(void* buf, size_t num_bytes) = 0;
+  virtual ~ReadableWav() {}
+};
+
+enum WavFormat {
+  kWavFormatPcm   = 1,  // PCM, each sample of size bytes_per_sample
+  kWavFormatALaw  = 6,  // 8-bit ITU-T G.711 A-law
+  kWavFormatMuLaw = 7,  // 8-bit ITU-T G.711 mu-law
+};
+
+// Return true if the given parameters will make a well-formed WAV header.
+bool CheckWavParameters(int num_channels,
+                        int sample_rate,
+                        WavFormat format,
+                        int bytes_per_sample,
+                        uint32_t num_samples);
+
+// Write a kWavHeaderSize bytes long WAV header to buf. The payload that
+// follows the header is supposed to have the specified number of interleaved
+// channels and contain the specified total number of samples of the specified
+// type. CHECKs the input parameters for validity.
+void WriteWavHeader(uint8_t* buf,
+                    int num_channels,
+                    int sample_rate,
+                    WavFormat format,
+                    int bytes_per_sample,
+                    uint32_t num_samples);
+
+// Read a WAV header from an implemented ReadableWav and parse the values into
+// the provided output parameters. ReadableWav is used because the header can
+// be variably sized. Returns false if the header is invalid.
+bool ReadWavHeader(ReadableWav* readable,
+                   int* num_channels,
+                   int* sample_rate,
+                   WavFormat* format,
+                   int* bytes_per_sample,
+                   uint32_t* num_samples);
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_COMMON_AUDIO_WAV_HEADER_H_