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

media/audio/audio_input_controller.h

Index: media/audio/audio_input_controller.h
diff --git a/media/audio/audio_input_controller.h b/media/audio/audio_input_controller.h
index 6f14394d0b397e4ed3a43df6ec3c5302d92d7964..26b715115bf2094d8f2bd31c98042e0dab24b31c 100644
--- a/media/audio/audio_input_controller.h
+++ b/media/audio/audio_input_controller.h
@@ -8,6 +8,7 @@
 #include <string>
 #include "base/atomicops.h"
 #include "base/callback.h"
+#include "base/files/file.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
@@ -79,6 +80,7 @@ namespace media {
 #define AUDIO_POWER_MONITORING
 #endif
 
+class AudioInputWriter;
 class UserInputMonitor;
 
 class MEDIA_EXPORT AudioInputController
@@ -229,6 +231,13 @@ class MEDIA_EXPORT AudioInputController
 
   bool SharedMemoryAndSyncSocketMode() const { return sync_writer_ != NULL; }
 
+  // Enable debug recording of audio input.
+  void EnableDebugRecording(AudioInputWriter* input_writer);
+
+  // Disbale debug recording of audio input. Must be called before owner of
+  // |input_writer| deletes it.
+  void DisableDebugRecording(const base::Closure& callback);
+
  protected:
   friend class base::RefCountedThreadSafe<AudioInputController>;
 
@@ -303,6 +312,14 @@ class MEDIA_EXPORT AudioInputController
   void LogSilenceState(SilenceState value);
 #endif
 
+  // Enable and disable debug recording of audio input. Called on the audio
+  // thread.
+  void DoEnableDebugRecording(AudioInputWriter* input_writer);
+  void DoDisableDebugRecording();
+
+  // Called on the audio thread.
+  void WriteInputDataForDebugging(scoped_ptr<AudioBus> data);
+
   // Gives access to the task runner of the creating thread.
   scoped_refptr<base::SingleThreadTaskRunner> creator_task_runner_;
 
@@ -366,6 +383,9 @@ class MEDIA_EXPORT AudioInputController
   // Time when a low-latency stream is created.
   base::TimeTicks low_latency_create_time_;
 
+  // Used for audio debug recordings. Accessed on audio thread.
+  AudioInputWriter* input_writer_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioInputController);
 };