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 1ef8d263755e695e4f7f344eeb4bc039a2cb0e54..c475b6a68c9d475bac480a21dc8f973c065e4924 100644
--- a/media/filters/chunk_demuxer.h
+++ b/media/filters/chunk_demuxer.h
@@ -56,6 +56,13 @@ class MEDIA_EXPORT ChunkDemuxerStream : public DemuxerStream {
   void Remove(base::TimeDelta start, base::TimeDelta end,
               base::TimeDelta duration);
 
+  // If the buffer is full, runs Frame Removal 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 EvictFrames(DecodeTimestamp media_time);
+
   // Signal to the stream that duration has changed to |duration|.
   void OnSetDuration(base::TimeDelta duration);
 
@@ -145,6 +152,8 @@ class MEDIA_EXPORT ChunkDemuxer : public Demuxer {
 
   typedef base::Closure InitSegmentReceivedCB;
 
+  typedef base::Callback<base::TimeDelta(void)> GetMediaTimeCB;
+
   // |open_cb| Run when Initialize() is called to signal that the demuxer
   //   is ready to receive media data via AppenData().
   // |encrypted_media_init_data_cb| Run when the demuxer determines that an
@@ -152,12 +161,15 @@ class MEDIA_EXPORT ChunkDemuxer : public Demuxer {
   // |enable_text| Process inband text tracks in the normal way when true,
   //   otherwise ignore them.
   // |log_cb| Run when the demuxer needs to emit MediaLog messages.
+  // |get_media_time_cb| Should return current media playback time, which
+  //   is used to ensure unconsumed data is not garbage collected.
   // |splice_frames_enabled| Indicates that it's okay to generate splice frames
   //   per the MSE specification.  Renderers must understand DecoderBuffer's
   //   splice_timestamp() field.
   ChunkDemuxer(const base::Closure& open_cb,
                const EncryptedMediaInitDataCB& encrypted_media_init_data_cb,
                const LogCB& log_cb,
+               const GetMediaTimeCB& get_media_time_cb,
                const scoped_refptr<MediaLog>& media_log,
                bool splice_frames_enabled);
   ~ChunkDemuxer() override;
@@ -241,6 +253,8 @@ class MEDIA_EXPORT ChunkDemuxer : public Demuxer {
   void Remove(const std::string& id, base::TimeDelta start,
               base::TimeDelta end);
 
+  bool EvictFrames();
+
   // Returns the current presentation duration.
   double GetDuration();
   double GetDuration_Locked();
@@ -362,6 +376,7 @@ class MEDIA_EXPORT ChunkDemuxer : public Demuxer {
   // Callback used to report log messages that can help the web developer
   // figure out what is wrong with the content.
   LogCB log_cb_;
+  GetMediaTimeCB get_media_time_cb_;
   scoped_refptr<MediaLog> media_log_;
 
   PipelineStatusCB init_cb_;