Make memory pressure notifier configurable

base/memory/memory_pressure_monitor_chromeos.h

 // Copyright 2014 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 BASE_MEMORY_MEMORY_PRESSURE_MONITOR_CHROMEOS_H_
 #define BASE_MEMORY_MEMORY_PRESSURE_MONITOR_CHROMEOS_H_
 
 #include "base/base_export.h"
 #include "base/files/scoped_file.h"
 #include "base/macros.h"
@@ skipping 43 matching lines @@
 
   // Redo the memory pressure calculation soon and call again if a critical
   // memory pressure prevails. Note that this call will trigger an asynchronous
   // action which gives the system time to release memory back into the pool.
   void ScheduleEarlyCheck();
 
   // Get the current memory pressure level.
   MemoryPressureListener::MemoryPressureLevel GetCurrentPressureLevel() const
       override;
 
+  void SetDispatchCallback(DispatchCallback callback) override;

[danakj, 2016/07/08 00:03:53]

nit: normally all overrides for a class are grouped into one block (no
whitespace), with a "ThisOtherClass implementation." comment or the like on the
top of them.

[bashi, 2016/07/08 00:13:05]

Acknowledged.

+
   // Returns a type-casted version of the current memory pressure monitor. A
   // simple wrapper to base::MemoryPressureMonitor::Get.
   static MemoryPressureMonitor* Get();
 
  private:
   friend TestMemoryPressureMonitor;
   // Starts observing the memory fill level.
   // Calls to StartObserving should always be matched with calls to
   // StopObserving.
   void StartObserving();
@@ skipping 26 matching lines @@
   // gets used to count the number of events since the last event occured.
   int moderate_pressure_repeat_count_;
 
   // The thresholds for moderate and critical pressure.
   const int moderate_pressure_threshold_percent_;
   const int critical_pressure_threshold_percent_;
 
   // File descriptor used to detect low memory condition.
   ScopedFD low_mem_file_;
 
+  DispatchCallback dispatch_callback_ =
+      &MemoryPressureListener::NotifyMemoryPressure;
+
   base::WeakPtrFactory<MemoryPressureMonitor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryPressureMonitor);
 };
 
 }  // namespace chromeos
 }  // namespace base
 
 #endif  // BASE_MEMORY_MEMORY_PRESSURE_MONITOR_CHROMEOS_H_