Experiment with more aggressive MSE GC on memory pressure

media/filters/source_buffer_state.h

Index: media/filters/source_buffer_state.h
diff --git a/media/filters/source_buffer_state.h b/media/filters/source_buffer_state.h
index 269cf326d0d5826f886f085c85abb91bcf049cb5..ecf0dbc73a5312ebbff6a4286b08772183b72fc1 100644
--- a/media/filters/source_buffer_state.h
+++ b/media/filters/source_buffer_state.h
@@ -9,6 +9,7 @@
 
 #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"
@@ -69,11 +70,15 @@ class MEDIA_EXPORT SourceBufferState {
   // 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);
+  // Runs the "Coded Frame Eviction Algorithm" from the Media Source Extensions
+  // spec: https://w3c.github.io/media-source/#sourcebuffer-coded-frame-eviction
+  // |eviction_size| is an input parameter specifying how much space we want to
+  // be available in the buffer after eviction.
+  bool EvictCodedFrames(DecodeTimestamp media_time, size_t eviction_size);
+
+  void OnMemoryPressure(
+      DecodeTimestamp media_time,
+      base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);
 
   // Returns true if currently parsing a media segment, or false otherwise.
   bool parsing_media_segment() const { return parsing_media_segment_; }