[Experiment] purge-and-suspend

cc/resources/resource_pool.h

Index: cc/resources/resource_pool.h
diff --git a/cc/resources/resource_pool.h b/cc/resources/resource_pool.h
index 4c63c6f6c0b67f632a57944481e6daf9a659e229..9feea62e975e981171ccb473629e21959c98fb95 100644
--- a/cc/resources/resource_pool.h
+++ b/cc/resources/resource_pool.h
@@ -13,6 +13,7 @@
 #include <memory>
 
 #include "base/macros.h"
+#include "base/memory/memory_pressure_listener.h"
 #include "base/memory/ptr_util.h"
 #include "base/trace_event/memory_dump_provider.h"
 #include "cc/base/cc_export.h"
@@ -127,6 +128,9 @@ class CC_EXPORT ResourcePool : public base::trace_event::MemoryDumpProvider {
       uint64_t new_content_id,
       const gfx::Rect& new_invalidated_rect);
 
+  void OnMemoryPressure(
+      base::MemoryPressureListener::MemoryPressureLevel memory_pressure_level);
+
   // Functions which manage periodic eviction of expired resources.
   void ScheduleEvictExpiredResourcesIn(base::TimeDelta time_from_now);
   void EvictExpiredResources();
@@ -147,6 +151,8 @@ class CC_EXPORT ResourcePool : public base::trace_event::MemoryDumpProvider {
   ResourceDeque unused_resources_;
   ResourceDeque busy_resources_;
 
+  std::unique_ptr<base::MemoryPressureListener> memory_pressure_listener_;
+
   using InUseResourceMap = std::map<ResourceId, std::unique_ptr<PoolResource>>;
   InUseResourceMap in_use_resources_;