Audio output debug recording.

media/audio/audio_file_writer.h

Index: media/audio/audio_file_writer.h
diff --git a/media/audio/audio_file_writer.h b/media/audio/audio_file_writer.h
index e7f8f48ab7941ef556b14e4ed9b3de4e2f280045..34c41caa1b9212b9670622dc0af38d91919a5c46 100644
--- a/media/audio/audio_file_writer.h
+++ b/media/audio/audio_file_writer.h
@@ -7,9 +7,16 @@
 
 #include <memory>
 
+#include "base/callback_forward.h"
+
+namespace base {
+class FilePath;
+}
+
 namespace media {
 
 class AudioBus;
+class AudioParameters;
 
 // A writer interface used for writing audio data to file for debugging
 // purposes.
@@ -36,6 +43,10 @@ class AudioFileWriter {
   virtual bool WillWrite() = 0;
 };
 
+// Used for creating an AudioFileWriter.
+using CreateAudioFileWriterCallback =
+    base::Callback<std::unique_ptr<AudioFileWriter>(const AudioParameters&)>;
+
 }  // namspace media
 
 #endif  // MEDIA_AUDIO_AUDIO_FILE_WRITER_H_