Enable round-tripping and updating of WebSourceBufferImpl timestamp offset

media/filters/chunk_demuxer.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_FILTERS_CHUNK_DEMUXER_H_
 #define MEDIA_FILTERS_CHUNK_DEMUXER_H_
 
 #include <map>
 #include <string>
 #include <utility>
@@ skipping 106 matching lines @@
   // Notifies the demuxer that the duration of the media has changed to
   // |duration|.
   void SetDuration(double duration);
 
   // Sets a time |offset| to be applied to subsequent buffers appended to the
   // source buffer associated with |id|. Returns true if the offset is set
   // properly, false if the offset cannot be applied because we're in the
   // middle of parsing a media segment.
   bool SetTimestampOffset(const std::string& id, base::TimeDelta offset);
 
+  // Retrieves the current offset being applied to subsequent buffers appended
+  // to the source buffer associated with |id|. If the implementation has not
+  // changed the offset since construction or the last SetTimestampOffset(),
+  // returns kNoTimestamp() instead to indicate it has not been updated.
+  base::TimeDelta GetUpdatedTimestampOffset(const std::string& id);
+
   // Set the append mode to be applied to subsequent buffers appended to the
   // source buffer associated with |id|. If |sequence_mode| is true, caller
   // is requesting "sequence" mode. Otherwise, caller is requesting "segments"
   // mode. Returns true if the mode update was allowed. Returns false if
   // the mode cannot be updated because we're in the middle of parsing a media
   // segment.
   // In "sequence" mode, appended media will be treated as adjacent in time.
   // In "segments" mode, timestamps in appended media determine coded frame
   // placement.
   bool SetSequenceMode(const std::string& id, bool sequence_mode);
@@ skipping 140 matching lines @@
   // removed with RemoveID() but can not be re-added (yet).
   std::string source_id_audio_;
   std::string source_id_video_;
 
   DISALLOW_COPY_AND_ASSIGN(ChunkDemuxer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_CHUNK_DEMUXER_H_