Implement evictFrames() to support MSE's coded frame eviction algorithm.

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 6e8bdf95c7cde7cd6e767cf9c7b862f0ec0ec1fc..075789b64445332b93519dfe57d7324827b1eba9 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();
+
   // Signal to the stream that duration has changed to |duration|.
   void OnSetDuration(base::TimeDelta duration);
 
@@ -242,6 +249,8 @@ 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();