Fix MSE GC, make it less aggressive, more spec-compliant

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 d5224c7e4ceb5d6334b763bec5b6f99b9598a53b..eb4b8555db800ee9538ad90361bd5453c0c4c065 100644
--- a/media/filters/chunk_demuxer.h
+++ b/media/filters/chunk_demuxer.h
@@ -57,6 +57,12 @@ class MEDIA_EXPORT ChunkDemuxerStream : public DemuxerStream {
   void Remove(base::TimeDelta start, base::TimeDelta end,
               base::TimeDelta duration);
 
+  // If the buffer is full, attempts to try to free up space, as specified in
+  // the "Coded Frame Eviction Algorithm" in the Media Source Extensions Spec.
+  // Returns false iff buffer is still full after running eviction.
+  // https://w3c.github.io/media-source/#sourcebuffer-coded-frame-eviction
+  bool EvictCodedFrames(DecodeTimestamp media_time);
+
   // Signal to the stream that duration has changed to |duration|.
   void OnSetDuration(base::TimeDelta duration);
 
@@ -244,6 +250,8 @@ class MEDIA_EXPORT ChunkDemuxer : public Demuxer {
   void Remove(const std::string& id, base::TimeDelta start,
               base::TimeDelta end);
 
+  bool EvictCodedFrames(base::TimeDelta currentMediaTime);
+
   // Returns the current presentation duration.
   double GetDuration();
   double GetDuration_Locked();