[Mac] Report statistics more regularly in Mac memory pressure monitor

base/memory/memory_pressure_monitor_win.h

 // Copyright 2015 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_WIN_H_
 #define BASE_MEMORY_MEMORY_PRESSURE_MONITOR_WIN_H_
 
 #include "base/base_export.h"
 #include "base/macros.h"
 #include "base/memory/memory_pressure_listener.h"
@@ skipping 44 matching lines @@
   // free memory below which the applicable memory pressure state engages.
   MemoryPressureMonitor(int moderate_threshold_mb, int critical_threshold_mb);
 
   ~MemoryPressureMonitor() override;
 
   // Schedules a memory pressure check to run soon. This must be called on the
   // same thread where the monitor was instantiated.
   void CheckMemoryPressureSoon();
 
   // Get the current memory pressure level. This can be called from any thread.
-  MemoryPressureLevel GetCurrentPressureLevel() const override;
+  MemoryPressureLevel GetCurrentPressureLevel() override;
   void SetDispatchCallback(const DispatchCallback& callback) override;
 
   // Returns the moderate pressure level free memory threshold, in MB.
   int moderate_threshold_mb() const { return moderate_threshold_mb_; }
 
   // Returns the critical pressure level free memory threshold, in MB.
   int critical_threshold_mb() const { return critical_threshold_mb_; }
 
  protected:
   // Internals are exposed for unittests.
@@ skipping 63 matching lines @@
   // CheckMemoryPressure/CheckMemoryPressureAndRecordStatistics via |timer_|.
   base::WeakPtrFactory<MemoryPressureMonitor> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MemoryPressureMonitor);
 };
 
 }  // namespace win
 }  // namespace base
 
 #endif  // BASE_MEMORY_MEMORY_PRESSURE_MONITOR_WIN_H_