Introduce media::AudioPushFifo and a couple of use cases (and clean-ups).

media/base/audio_fifo.h

Index: media/base/audio_fifo.h
diff --git a/media/base/audio_fifo.h b/media/base/audio_fifo.h
index 213a61e9b2abb85a71ebd58df471ed974297419c..25dabf7e15af731fb55e6329ade87a3dcc86fdf3 100644
--- a/media/base/audio_fifo.h
+++ b/media/base/audio_fifo.h
@@ -16,6 +16,9 @@ namespace media {
 // can not be extended dynamically.  The allocated memory is utilized as a
 // ring buffer.
 // This class is thread-unsafe.
+//

[DaleCurtis, 2016/02/20 00:07:22]

Ditto.

[miu, 2016/02/23 04:27:41]

Done.

+// NOTE: Consider using the more-efficient and easier-to-use AudioRechunker
+// instead of this FIFO implementation.
 class MEDIA_EXPORT AudioFifo {
  public:
   // Creates a new AudioFifo and allocates |channels| of length |frames|.