Add plumbing and support for crossfading StreamParserBuffers.

media/filters/source_buffer_stream.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.
 
 // SourceBufferStream is a data structure that stores media Buffers in ranges.
 // Buffers can be appended out of presentation order. Buffers are retrieved by
 // seeking to the desired start point and calling GetNextBuffer(). Buffers are
 // returned in sequential presentation order.
 
 #ifndef MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_
@@ skipping 275 matching lines @@
   // timestamps that match |start| will be removed.
   // |*deleted_buffers| - Filled with buffers for the current playback position
   // if the removal range included the current playback position. These buffers
   // can be used as candidates for placing in the |track_buffer_|.
   void RemoveInternal(
       base::TimeDelta start, base::TimeDelta end, bool is_exclusive,
       BufferQueue* deleted_buffers);
 
   bool is_video() const { return video_configs_.size() > 0; }
 
+  // See GetNextBuffer().

[acolwell GONE FROM CHROMIUM, 2014/01/10 22:53:31]

nit: It would be good to at least outline the division of responsibility between
GetNextBuffer() and GetNextBufferInternal().

+  Status GetNextBufferInternal(scoped_refptr<StreamParserBuffer>* out_buffer);
+
   // Callback used to report error strings that can help the web developer
   // figure out what is wrong with the content.
   LogCB log_cb_;
 
   // List of disjoint buffered ranges, ordered by start time.
   RangeList ranges_;
 
   // Indicates which decoder config is being used by the decoder.
   // GetNextBuffer() is only allows to return buffers that have a
   // config ID that matches this index. If there is a mismatch then
@@ skipping 56 matching lines @@
 
   // The maximum amount of data in bytes the stream will keep in memory.
   int memory_limit_;
 
   // Indicates that a kConfigChanged status has been reported by GetNextBuffer()
   // and GetCurrentXXXDecoderConfig() must be called to update the current
   // config. GetNextBuffer() must not be called again until
   // GetCurrentXXXDecoderConfig() has been called.
   bool config_change_pending_;
 
+  // Used by GetNextBuffer() when a buffer with fade out is returned from
+  // GetNextBufferInternal().  Will be set to the returned buffer and will be
+  // consumed after the fade out section has been exhausted.
+  scoped_refptr<StreamParserBuffer> fade_in_buffer_;
+
+  // Indicates which of the fade out preroll buffers in |fade_in_buffer_| should
+  // be handled out next.
+  size_t fade_out_preroll_index_;
+
+
   DISALLOW_COPY_AND_ASSIGN(SourceBufferStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_