The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8ceca0e580766a9f91cf655a52de1ebd97d8443d

commit 8ceca0e580766a9f91cf655a52de1ebd97d8443d
Author: bcwhite <bcwhite@chromium.org>
Date: Fri Sep 09 16:57:12 2016

Added MemoryMonitor for Linux (with test).

Extraction of common code also means some changes to the
Windows memory-monitor.

BUG= 644397 

Review-Url: https://codereview.chromium.org/2310193002
Cr-Commit-Position: refs/heads/master@{#417607}

[modify] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/BUILD.gn
[add] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/memory_monitor.cc
[modify] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/memory_monitor.h
[add] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/memory_monitor_linux.cc
[add] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/memory_monitor_linux.h
[add] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/memory_monitor_linux_unittest.cc
[modify] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/memory_monitor_win.cc
[modify] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/memory_monitor_win.h
[modify] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/memory_monitor_win_unittest.cc
[add] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/test_memory_monitor.cc
[add] https://crrev.com/8ceca0e580766a9f91cf655a52de1ebd97d8443d/components/memory_coordinator/browser/test_memory_monitor.h

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/98900b02d86546533cfcb95356db7d327bb31204

commit 98900b02d86546533cfcb95356db7d327bb31204
Author: bcwhite <bcwhite@chromium.org>
Date: Mon Sep 19 20:13:03 2016

Added memory-monitor for ChromeOS.

BUG= 644397 

Review-Url: https://codereview.chromium.org/2332423002
Cr-Commit-Position: refs/heads/master@{#419544}

[modify] https://crrev.com/98900b02d86546533cfcb95356db7d327bb31204/content/browser/BUILD.gn
[add] https://crrev.com/98900b02d86546533cfcb95356db7d327bb31204/content/browser/memory/memory_monitor_chromeos.cc
[add] https://crrev.com/98900b02d86546533cfcb95356db7d327bb31204/content/browser/memory/memory_monitor_chromeos.h
[add] https://crrev.com/98900b02d86546533cfcb95356db7d327bb31204/content/browser/memory/memory_monitor_chromeos_unittest.cc
[modify] https://crrev.com/98900b02d86546533cfcb95356db7d327bb31204/content/browser/memory/memory_monitor_linux.h
[modify] https://crrev.com/98900b02d86546533cfcb95356db7d327bb31204/content/test/BUILD.gn

My understanding is that this is now obsolete.  The uncommitted Mac one is here:
https://codereview.chromium.org/2360433002/  (closed)