Experiment with more aggressive MSE GC on memory pressure

media/filters/source_buffer_state.h

 // Copyright (c) 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_FILTERS_SOURCE_BUFFER_STATE_H_
 #define MEDIA_FILTERS_SOURCE_BUFFER_STATE_H_
 
 #include <list>
 
 #include "base/bind.h"
 #include "base/macros.h"
+#include "base/memory/memory_pressure_listener.h"
 #include "media/base/audio_codecs.h"
 #include "media/base/demuxer.h"
 #include "media/base/demuxer_stream.h"
 #include "media/base/media_export.h"
 #include "media/base/media_log.h"
 #include "media/base/stream_parser.h"
 #include "media/base/stream_parser_buffer.h"
 #include "media/base/video_codecs.h"
 
 namespace media {
@@ skipping 46 matching lines @@
   // Calls Remove(|start|, |end|, |duration|) on all
   // ChunkDemuxerStreams managed by this object.
   void Remove(TimeDelta start, TimeDelta end, 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, size_t newDataSize);
 
+  // Gets invoked when the system is experiencing memory pressure, i.e. there's
+  // not enough free memory. The |media_time| is the media playback position at
+  // the time of memory pressure notification (needed for accurate GC). The
+  // |memory_pressure_listener| indicates memory pressure severity. The
+  // |force_instant_gc| is used to force the MSE garbage collection algorithm to
+  // be run right away, without waiting for the next append.
+  void OnMemoryPressure(
+      DecodeTimestamp media_time,
+      base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level,
+      bool force_instant_gc);
+
   // Returns true if currently parsing a media segment, or false otherwise.
   bool parsing_media_segment() const { return parsing_media_segment_; }
 
   // Sets |frame_processor_|'s sequence mode to |sequence_mode|.
   void SetSequenceMode(bool sequence_mode);
 
   // Signals the coded frame processor to update its group start timestamp to be
   // |timestamp_offset| if it is in sequence append mode.
   void SetGroupStartTimestampIfInSequenceMode(base::TimeDelta timestamp_offset);
 
@@ skipping 132 matching lines @@
   // TODO(wolenetz): Refactor this function while integrating April 29, 2014
   // changes to MSE spec. See http://crbug.com/371499.
   bool auto_update_timestamp_offset_;
 
   DISALLOW_COPY_AND_ASSIGN(SourceBufferState);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_SOURCE_BUFFER_STATE_H_