The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fb11bbe1e11b29ad870bdf5a940847dda841f542

commit fb11bbe1e11b29ad870bdf5a940847dda841f542
Author: shrike <shrike@chromium.org>
Date: Tue May 16 18:30:30 2017

[Mac] Fix race condition in memory pressure level reporting.

The change in https://codereview.chromium.org/2743253006 stops the Mac
memory pressure monitor from checking the current pressure level
directly on each call to GetCurrentPressureLevel(). However, if the OS
sends a pressure change notification, callers of
GetCurrentPressureLevel() may receive the old pressure level. This cl
fixes the race condition by forcing an internal pressure level update
upon receiving a pressure level change notification from the OS.

R=brettw@chromium.org,mark@chromium.org
BUG= 720924 

Review-Url: https://codereview.chromium.org/2877573002
Cr-Commit-Position: refs/heads/master@{#472171}

[modify] https://crrev.com/fb11bbe1e11b29ad870bdf5a940847dda841f542/base/memory/memory_pressure_monitor_mac.cc