Add a ref counted audio bus.

media/base/audio_bus.h

Index: media/base/audio_bus.h
diff --git a/media/base/audio_bus.h b/media/base/audio_bus.h
index c5b161f0236082728db2bd97b25ba9de7a9e1c60..c78486e5e00aa5f00ce567275f0025681778ec21 100644
--- a/media/base/audio_bus.h
+++ b/media/base/audio_bus.h
@@ -8,6 +8,7 @@
 #include <vector>
 
 #include "base/memory/aligned_memory.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "media/base/media_export.h"
 
@@ -110,12 +111,13 @@ class MEDIA_EXPORT AudioBus {
 
   virtual ~AudioBus();
 
- private:
+ protected:
   AudioBus(int channels, int frames);
   AudioBus(int channels, int frames, float* data);
   AudioBus(int frames, const std::vector<float*>& channel_data);
   explicit AudioBus(int channels);
 
+ private:
   // Helper method for building |channel_data_| from a block of memory.  |data|
   // must be at least BlockSize() bytes in size.
   void BuildChannelData(int channels, int aligned_frame, float* data);
@@ -132,6 +134,24 @@ class MEDIA_EXPORT AudioBus {
   DISALLOW_COPY_AND_ASSIGN(AudioBus);
 };
 
+// RefCounted version of AudioBus. This is not meant for general use. Only use
+// this when your lifetime requirements make it impossible to use an
+// AudioBus scoped_ptr.
+class MEDIA_EXPORT AudioBusRefCounted
+    : public media::AudioBus,
+      public base::RefCountedThreadSafe<AudioBusRefCounted> {
+ public:
+  static scoped_refptr<AudioBusRefCounted> Create(int channels, int frames);
+
+ private:
+  friend class base::RefCountedThreadSafe<AudioBusRefCounted>;
+
+  AudioBusRefCounted(int channels, int frames);
+  virtual ~AudioBusRefCounted();
+
+  DISALLOW_COPY_AND_ASSIGN(AudioBusRefCounted);
+};
+
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_BUS_H_