Update the WebMediaSourceClientImpl & ChunkDemuxer to received explicit end of stream cancellation.

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 assicated 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);
 
-  // Signals an EndOfStream request.
-  void EndOfStream(PipelineStatus status);
+  // Called to signal changes in the "end of stream"
+  // state. UnmarkEndOfStream() must not be called if a matching
+  // MarkEndOfStream() has not come before it.
+  void MarkEndOfStream(PipelineStatus status);
+  void UnmarkEndOfStream();
+
   void Shutdown();
 
   void SetMemoryLimitsForTesting(int memory_limit);
 
  private:
   enum State {
     WAITING_FOR_INIT,
     INITIALIZING,
     INITIALIZED,
     ENDED,
@@ skipping 106 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_