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

content/browser/memory/memory_condition_observer.h

 // Copyright 2016 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.
 
 #ifndef CONTENT_BROWSER_MEMORY_MEMORY_CONDITION_OBSERVER_H_
 #define CONTENT_BROWSER_MEMORY_MEMORY_CONDITION_OBSERVER_H_
 
 #include "base/cancelable_callback.h"
 #include "base/single_thread_task_runner.h"
 #include "base/time/time.h"
 #include "content/browser/memory/memory_coordinator_impl.h"
 #include "content/common/content_export.h"
 
+#if defined(OS_CHROMEOS)
+#include "base/memory/low_memory_observer_chromeos.h"
+#endif
+
 namespace content {
 
 // MemoryConditionObserver is an internal implementation of MemoryCoordinator
 // which uses a heuristic to determine the current memory condition. The
 // heuristic is:
 // * Compute number of renderers which can be created until the system will
 //   be in a critical state. Call this N.
 //   (See memory_monitor.h for the definition of "critical")
 // * Covert N to memory condition (one of NORMAL/WARNING/CRITICAL) by using some
 //   thresholds and hysteresis.
@@ skipping 29 matching lines @@
   // a heuristic.
   MemoryCondition CalculateNextCondition();
 
   // Periodically called to update the memory condition.
   void UpdateCondition();
 
   MemoryCoordinatorImpl* coordinator_;
   scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
   base::CancelableClosure update_condition_closure_;
 
+#if defined(OS_CHROMEOS)
+  std::unique_ptr<base::chromeos::LowMemoryObserver> low_memory_observer_;
+#endif
+
   // Sets up parameters for the heuristic.
   void InitializeParameters();
 
   // Validates parameters defined below.
   bool ValidateParameters();
 
   // Parameters to control the heuristic.
 
   // The median size of a renderer on the current platform. This is used to
   // convert the amount of free memory to an expected number of new renderers
@@ skipping 20 matching lines @@
   base::TimeDelta monitoring_interval_foregrounded_;
   // The value of |monitoring_interval_| when the browser is backgrounded.
   base::TimeDelta monitoring_interval_backgrounded_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryConditionObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_MEMORY_MEMORY_CONDITION_OBSERVER_H_