[Experiment] purge-and-suspend

cc/raster/staging_buffer_pool.h

Index: cc/raster/staging_buffer_pool.h
diff --git a/cc/raster/staging_buffer_pool.h b/cc/raster/staging_buffer_pool.h
index faa012b2b8029192b97400a1b48ff5491d82d3f9..bbb448cc649e6c2cee1678c86e94ff1250e7c80f 100644
--- a/cc/raster/staging_buffer_pool.h
+++ b/cc/raster/staging_buffer_pool.h
@@ -12,6 +12,7 @@
 #include <set>
 
 #include "base/macros.h"
+#include "base/memory/memory_pressure_listener.h"
 #include "base/memory/weak_ptr.h"
 #include "base/synchronization/lock.h"
 #include "base/time/time.h"
@@ -78,6 +79,8 @@ class CC_EXPORT StagingBufferPool
   void MarkStagingBufferAsBusy(const StagingBuffer* staging_buffer);
 
   base::TimeTicks GetUsageTimeForLRUBuffer();
+  void OnMemoryPressure(
+      base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);
   void ScheduleReduceMemoryUsage();
   void ReduceMemoryUsage();
   void ReleaseBuffersNotUsedSince(base::TimeTicks time);
@@ -91,6 +94,7 @@ class CC_EXPORT StagingBufferPool
   ContextProvider* const worker_context_provider_;
   ResourceProvider* const resource_provider_;
   const bool use_partial_raster_;
+  std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
 
   mutable base::Lock lock_;
   // |lock_| must be acquired when accessing the following members.