WIP: memory coordinator: Check /dev/chromeos-low-mem to determine memory condition

base/memory/memory_pressure_monitor_chromeos.h

Index: base/memory/memory_pressure_monitor_chromeos.h
diff --git a/base/memory/memory_pressure_monitor_chromeos.h b/base/memory/memory_pressure_monitor_chromeos.h
index 563ba85081f94664fa6d1322387a0fdf632f62d4..920e522eb0e626bf65105071ae125e303f098084 100644
--- a/base/memory/memory_pressure_monitor_chromeos.h
+++ b/base/memory/memory_pressure_monitor_chromeos.h
@@ -6,8 +6,8 @@
 #define BASE_MEMORY_MEMORY_PRESSURE_MONITOR_CHROMEOS_H_
 
 #include "base/base_export.h"
-#include "base/files/scoped_file.h"
 #include "base/macros.h"
+#include "base/memory/low_memory_observer_chromeos.h"
 #include "base/memory/memory_pressure_listener.h"
 #include "base/memory/memory_pressure_monitor.h"
 #include "base/memory/weak_ptr.h"
@@ -112,8 +112,8 @@ class BASE_EXPORT MemoryPressureMonitor : public base::MemoryPressureMonitor {
   const int moderate_pressure_threshold_percent_;
   const int critical_pressure_threshold_percent_;
 
-  // File descriptor used to detect low memory condition.
-  ScopedFD low_mem_file_;
+  // To detect low memory condition.
+  std::unique_ptr<LowMemoryObserver> low_mem_observer_;
 
   DispatchCallback dispatch_callback_;