Remove buffer duration calculation from WebMClusterParser and update SourceBufferStream accordingly

media/base/stream_parser_buffer.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_STREAM_PARSER_BUFFER_H_
 #define MEDIA_BASE_STREAM_PARSER_BUFFER_H_
 
 #include "media/base/decoder_buffer.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 class MEDIA_EXPORT StreamParserBuffer : public DecoderBuffer {
  public:
   static scoped_refptr<StreamParserBuffer> CreateEOSBuffer();
   static scoped_refptr<StreamParserBuffer> CopyFrom(
       const uint8* data, int data_size, bool is_keyframe);
   bool IsKeyframe() const { return is_keyframe_; }
 
   // Decode timestamp. If not explicitly set, or set to kNoTimestamp(), the
   // value will be taken from the normal timestamp.
   base::TimeDelta GetDecodeTimestamp() const;
   void SetDecodeTimestamp(const base::TimeDelta& timestamp);
 
-  // Returns this buffer's decode timestamp + duration, assuming both are valid.
-  base::TimeDelta GetEndTimestamp() const;
-
  private:
   StreamParserBuffer(const uint8* data, int data_size, bool is_keyframe);
   virtual ~StreamParserBuffer();
 
   bool is_keyframe_;
   base::TimeDelta decode_timestamp_;
   DISALLOW_COPY_AND_ASSIGN(StreamParserBuffer);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_STREAM_PARSER_BUFFER_H_