Add AudioStreamRegistry. Move stream counting logic

media/audio/audio_streams_tracker.h

Index: media/audio/audio_streams_tracker.h
diff --git a/media/audio/audio_streams_tracker.h b/media/audio/audio_streams_tracker.h
index 1071fd717f363af9467e5c5732df6276f876bc96..f501a21893378393cda25ddced989ddfccbd475c 100644
--- a/media/audio/audio_streams_tracker.h
+++ b/media/audio/audio_streams_tracker.h
@@ -24,7 +24,7 @@ class MEDIA_EXPORT AudioStreamsTracker {
   // Increases/decreases current stream count. Updates max stream count if
   // current count is larger.
   void IncreaseStreamCount();
-  void DecreaseStreamCount(size_t count = 1);
+  void DecreaseStreamCount();
 
   // Resets the max stream count, i.e. sets it to the current stream count.
   void ResetMaxStreamCount();