Fix various operations in ChunkDemuxer that were not being applied to text tracks.

media/filters/chunk_demuxer.h

Index: media/filters/chunk_demuxer.h
diff --git a/media/filters/chunk_demuxer.h b/media/filters/chunk_demuxer.h
index d05063209e2d6bad3998a0738687f134a05a200e..5f37fc2ff0c783bfe4bd15a2a9fbf9d1a07b746e 100644
--- a/media/filters/chunk_demuxer.h
+++ b/media/filters/chunk_demuxer.h
@@ -137,6 +137,8 @@ class MEDIA_EXPORT ChunkDemuxer : public Demuxer {
 
   void Shutdown();
 
+  // Sets the memory limit on each stream. |memory_limit| is the
+  // maximum number of bytes each stream is allowed to hold in its buffer.
   void SetMemoryLimitsForTesting(int memory_limit);
 
   // Returns the ranges representing the buffered data in the demuxer.
@@ -218,6 +220,10 @@ class MEDIA_EXPORT ChunkDemuxer : public Demuxer {
   // Seeks all SourceBufferStreams to |seek_time|.
   void SeekAllSources(base::TimeDelta seek_time);
 
+  // Shuts down all DemuxerStreams by calling Shutdown() on
+  // all objects in |source_state_map_|.
+  void ShutdownAllStreams();
+
   mutable base::Lock lock_;
   State state_;
   bool cancel_next_seek_;