Remove AudioDecoder from the Filter heirarchy.

media/base/audio_decoder.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_DECODER_H_
+#define MEDIA_BASE_AUDIO_DECODER_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/time.h"
+#include "media/base/channel_layout.h"
+#include "media/base/demuxer_stream.h"
+#include "media/base/filters.h"
+#include "media/base/pipeline_status.h"
+#include "media/base/media_export.h"
+
+namespace media {
+
+class MEDIA_EXPORT AudioDecoder
+    : public base::RefCountedThreadSafe<AudioDecoder> {
+ public:
+  // Initialize a AudioDecoder with the given DemuxerStream, executing the
+  // callback upon completion.
+  // stats_callback is used to update global pipeline statistics.
+  virtual void Initialize(DemuxerStream* stream,

[scherkus (not reviewing), 2012/02/03 23:31:29]

I thought we agreed to do const scoped_refptr<T>& ?

[Ami GONE FROM CHROMIUM, 2012/02/04 00:10:21]

Not sure who 'we' is...  ffmpeg_audio_decoder.cc had this:

  // TODO(scherkus): change Initialize() signature to pass |stream| as a
  // scoped_refptr<>.

Done.

+                          const PipelineStatusCB& callback,
+                          const StatisticsCallback& stats_callback) = 0;
+
+  // Request samples to be decoded and returned via the provided callback.
+  // Only one read may be in flight at any given time.
+  //
+  // Implementations guarantee that the callback will not be called from within
+  // this method.
+  //
+  // Non-NULL sample buffer pointers will contain decoded audio data or may
+  // indicate the end of the stream. A NULL buffer pointer indicates an aborted
+  // Read(). This can happen if the DemuxerStream gets flushed and doesn't have
+  // any more data to return.
+  typedef base::Callback<void(scoped_refptr<Buffer>)> ReadCB;
+  virtual void Read(const ReadCB& callback) = 0;
+
+  // Returns various information about the decoded audio format.
+  virtual int bits_per_channel() = 0;
+  virtual ChannelLayout channel_layout() = 0;
+  virtual int samples_per_second() = 0;
+
+ protected:
+  friend class base::RefCountedThreadSafe<AudioDecoder>;
+  virtual ~AudioDecoder();
+  AudioDecoder();
+
+  DISALLOW_COPY_AND_ASSIGN(AudioDecoder);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_AUDIO_DECODER_H_