Experiment with more aggressive MSE GC on memory pressure

media/filters/source_buffer_stream.h

 // Copyright (c) 2012 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.
 
 // SourceBufferStream is a data structure that stores media Buffers in ranges.
 // Buffers can be appended out of presentation order. Buffers are retrieved by
 // seeking to the desired start point and calling GetNextBuffer(). Buffers are
 // returned in sequential presentation order.
 
 #ifndef MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_
 #define MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_
 
 #include <stddef.h>
 
 #include <deque>
 #include <list>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/macros.h"
+#include "base/memory/memory_pressure_listener.h"
 #include "base/memory/ref_counted.h"
 #include "media/base/audio_decoder_config.h"
 #include "media/base/media_export.h"
 #include "media/base/media_log.h"
 #include "media/base/ranges.h"
 #include "media/base/stream_parser_buffer.h"
 #include "media/base/text_track_config.h"
 #include "media/base/video_decoder_config.h"
 
 namespace media {
@@ skipping 54 matching lines @@
   // |duration| is the current duration of the presentation. It is
   // required by the computation outlined in the spec.
   void Remove(base::TimeDelta start, base::TimeDelta end,
               base::TimeDelta duration);
 
   // Frees up space if the SourceBufferStream is taking up too much memory.
   // |media_time| is current playback position.
   bool GarbageCollectIfNeeded(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);
+
   // Changes the SourceBufferStream's state so that it will start returning
   // buffers starting from the closest keyframe before |timestamp|.
   void Seek(base::TimeDelta timestamp);
 
   // Returns true if the SourceBufferStream has seeked to a time without
   // buffered data and is waiting for more data to be appended.
   bool IsSeekPending() const;
 
   // Notifies the SourceBufferStream that the media duration has been changed to
   // |duration| so it should drop any data past that point.
@@ skipping 317 matching lines @@
   bool last_appended_buffer_is_keyframe_ = false;
 
   // The decode timestamp on the last buffer returned by the most recent
   // GetNextBuffer() call. Set to kNoDecodeTimestamp() if GetNextBuffer() hasn't
   // been called yet or a seek has happened since the last GetNextBuffer() call.
   DecodeTimestamp last_output_buffer_timestamp_;
 
   // Stores the largest distance between two adjacent buffers in this stream.
   base::TimeDelta max_interbuffer_distance_;
 
+  base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level_ =
+      base::MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE;
+
   // The maximum amount of data in bytes the stream will keep in memory.
   size_t memory_limit_;
 
   // Indicates that a kConfigChanged status has been reported by GetNextBuffer()
   // and GetCurrentXXXDecoderConfig() must be called to update the current
   // config. GetNextBuffer() must not be called again until
   // GetCurrentXXXDecoderConfig() has been called.
   bool config_change_pending_ = false;
 
   // Used by HandleNextBufferWithPreroll() when a buffer with preroll is
   // returned from GetNextBufferInternal().
   scoped_refptr<StreamParserBuffer> pending_buffer_;
 
   // Indicates that all buffers before |pending_buffer_| have been handed out.
   bool pending_buffers_complete_ = false;
 
   // To prevent log spam, count the number of logs for different log scenarios.
   int num_splice_logs_ = 0;
   int num_track_buffer_gap_warning_logs_ = 0;
   int num_garbage_collect_algorithm_logs_ = 0;
   int num_strange_same_timestamps_logs_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(SourceBufferStream);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_FILTERS_SOURCE_BUFFER_STREAM_H_