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

media/base/audio_fifo.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_AUDIO_FIFO_H_
 #define MEDIA_BASE_AUDIO_FIFO_H_
 
 #include "base/macros.h"
 #include "media/base/audio_bus.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 // First-in first-out container for AudioBus elements.
 // The maximum number of audio frames in the FIFO is set at construction and
 // 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|.
   AudioFifo(int channels, int frames);
   virtual ~AudioFifo();
 
   // Pushes all audio channel data from |source| to the FIFO.
   // Push() will crash if the allocated space is insufficient.
   void Push(const AudioBus* source);
 
@@ skipping 29 matching lines @@
 
   // Current write position.
   int write_pos_;
 
   DISALLOW_COPY_AND_ASSIGN(AudioFifo);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_AUDIO_FIFO_H_