Fix free memory calculation.

components/memory_pressure/direct_memory_pressure_calculator_win.cc

 // 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.
 
 #include "components/memory_pressure/direct_memory_pressure_calculator_win.h"
 
 #include "base/logging.h"
 #include "base/process/process_metrics.h"
 
 namespace memory_pressure {
@@ skipping 47 matching lines @@
   DCHECK_LE(0, critical_threshold_mb_);
 }
 
 DirectMemoryPressureCalculator::MemoryPressureLevel
 DirectMemoryPressureCalculator::CalculateCurrentPressureLevel() {
   base::SystemMemoryInfoKB mem_info = {};
   if (!GetSystemMemoryInfo(&mem_info))
     return MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE;
 
   // How much system memory is actively available for use right now, in MBs.
-  int phys_free = mem_info.free / kKBperMB;
+  int phys_free = mem_info.avail_phys / kKBperMB;
 
   // TODO(chrisha): This should eventually care about address space pressure,
   // but the browser process (where this is running) effectively never runs out
   // of address space. Renderers occasionally do, but it does them no good to
   // have the browser process monitor address space pressure. Long term,
   // renderers should run their own address space pressure monitors and act
   // accordingly, with the browser making cross-process decisions based on
   // system memory pressure.
 
   // Determine if the physical memory is under critical memory pressure.
@@ skipping 28 matching lines @@
     critical_threshold_mb_ = kLargeMemoryDefaultCriticalThresholdMb;
   } else {
     moderate_threshold_mb_ = kSmallMemoryDefaultModerateThresholdMb;
     critical_threshold_mb_ = kSmallMemoryDefaultCriticalThresholdMb;
   }
 }
 
 #endif  // defined(MEMORY_PRESSURE_IS_POLLING)
 
 }  // namespace memory_pressure