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

media/filters/source_buffer_stream.cc

Index: media/filters/source_buffer_stream.cc
diff --git a/media/filters/source_buffer_stream.cc b/media/filters/source_buffer_stream.cc
index 2b96b36498ed0ef070efaa703f5d7bba0fd4986a..948ea012eaef6f1382339a7e695d4308a16c254e 100644
--- a/media/filters/source_buffer_stream.cc
+++ b/media/filters/source_buffer_stream.cc
@@ -1061,12 +1061,12 @@ Ranges<base::TimeDelta> SourceBufferStream::GetBufferedTime() const {
   return ranges;
 }
 
-void SourceBufferStream::EndOfStream() {
+void SourceBufferStream::MarkEndOfStream() {
   DCHECK(!end_of_stream_);
   end_of_stream_ = true;
 }
 
-void SourceBufferStream::CancelEndOfStream() {
+void SourceBufferStream::UnmarkEndOfStream() {
   DCHECK(end_of_stream_);
   end_of_stream_ = false;
 }