Revert 290359 "Remove AudioBuffersState class."

trunk/src/media/audio/audio_io.h

Index: trunk/src/media/audio/audio_io.h
===================================================================
--- trunk/src/media/audio/audio_io.h	(revision 290374)
+++ trunk/src/media/audio/audio_io.h	(working copy)
@@ -6,6 +6,7 @@
 #define MEDIA_AUDIO_AUDIO_IO_H_
 
 #include "base/basictypes.h"
+#include "media/audio/audio_buffers_state.h"
 #include "media/base/audio_bus.h"
 
 // Low-level audio output support. To make sound there are 3 objects involved:
@@ -57,10 +58,10 @@
   class MEDIA_EXPORT AudioSourceCallback {
    public:
     // Provide more data by fully filling |dest|.  The source will return
-    // the number of frames it filled.  |total_bytes_delay| contains current
-    // number of bytes of delay buffered by the AudioOutputStream.
+    // the number of frames it filled.  |buffers_state| contains current state
+    // of the buffers, and can be used by the source to calculate delay.
     virtual int OnMoreData(AudioBus* dest,
-                           int total_bytes_delay) = 0;
+                           AudioBuffersState buffers_state) = 0;
 
     // There was an error while playing a buffer. Audio source cannot be
     // destroyed yet. No direct action needed by the AudioStream, but it is