Implement writing mic audio input data to file for debugging purposes.

content/browser/renderer_host/media/audio_input_debug_writer.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "content/browser/renderer_host/media/audio_input_debug_writer.h"
+
+#include "content/public/browser/browser_thread.h"
+#include "media/base/audio_bus.h"
+
+namespace content {
+
+AudioInputDebugWriter::AudioInputDebugWriter(base::File file)
+    : file_(file.Pass()),
+      interleaved_data_size_(0),
+      weak_factory_(this) {
+}
+
+AudioInputDebugWriter::~AudioInputDebugWriter() {
+  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+}
+
+void AudioInputDebugWriter::Write(scoped_ptr<media::AudioBus> data) {
+  BrowserThread::PostTask(
+      BrowserThread::FILE,
+      FROM_HERE,
+      base::Bind(&AudioInputDebugWriter::DoWrite,
+                 weak_factory_.GetWeakPtr(),
+                 base::Passed(&data)));
+}
+
+void AudioInputDebugWriter::DoWrite(scoped_ptr<media::AudioBus> data) {
+  DCHECK_CURRENTLY_ON(BrowserThread::FILE);
+
+  // Convert to 16 bit audio and write to file.
+  int data_size = data->frames() * data->channels();
+  if (!interleaved_data_ || interleaved_data_size_ < data_size) {
+    interleaved_data_.reset(new int16[data_size]);
+    interleaved_data_size_ = data_size;
+  }
+  data->ToInterleaved(data->frames(), sizeof(interleaved_data_[0]),
+                      interleaved_data_.get());
+  file_.WriteAtCurrentPos(reinterpret_cast<char*>(interleaved_data_.get()),
+                          data_size * sizeof(interleaved_data_[0]));
+}
+
+}  // namspace content