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

media/audio/audio_input_writer.h

Index: media/audio/audio_input_writer.h
diff --git a/media/audio/audio_input_writer.h b/media/audio/audio_input_writer.h
new file mode 100644
index 0000000000000000000000000000000000000000..700570b0318eedfecd29278bcb9f8d65a3004ae6
--- /dev/null
+++ b/media/audio/audio_input_writer.h
@@ -0,0 +1,24 @@
+// 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.
+
+#ifndef MEDIA_AUDIO_AUDIO_INPUT_WRITER_H_
+#define MEDIA_AUDIO_AUDIO_INPUT_WRITER_H_
+
+namespace media {
+
+class AudioBus;
+
+// A writer interface used by AudioInputController for writing audio data to
+// file for debugging purposes.
+class AudioInputWriter {
+ public:
+  virtual ~AudioInputWriter() {}
+
+  // Write |data| to file.
+  virtual void Write(scoped_ptr<AudioBus> data) = 0;
+};
+
+}  // namspace media
+
+#endif  // MEDIA_AUDIO_AUDIO_INPUT_WRITER_H_