The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/867eb8078068308ce3562339254727df9b011565

commit 867eb8078068308ce3562339254727df9b011565
Author: Yuzu Saijo <yuzus@chromium.org>
Date: Thu Sep 27 01:14:55 2018

Add more memory metrics for OomIntervention to improve triggering

This CL adds more memory metrics when OomIntervention is enabled. This adds UMA of (1)renderer
memory usage reported every second and (2)time after navigation when intervention is triggered.

Bug: 888935
Change-Id: Iad60b53b47665db0e8b051df50221b9860dd8680
Reviewed-on: https://chromium-review.googlesource.com/1242732
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Yuzu Saijo <yuzus@chromium.org>
Cr-Commit-Position: refs/heads/master@{#594552}
[modify] https://crrev.com/867eb8078068308ce3562339254727df9b011565/chrome/browser/android/oom_intervention/oom_intervention_tab_helper.cc
[modify] https://crrev.com/867eb8078068308ce3562339254727df9b011565/third_party/blink/renderer/controller/oom_intervention_impl.cc
[modify] https://crrev.com/867eb8078068308ce3562339254727df9b011565/third_party/blink/renderer/controller/oom_intervention_impl.h
[modify] https://crrev.com/867eb8078068308ce3562339254727df9b011565/tools/metrics/histograms/histograms.xml

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/60addda9a6277ea88d60df67bc5a51cc90477233

commit 60addda9a6277ea88d60df67bc5a51cc90477233
Author: Yuzu Saijo <yuzus@chromium.org>
Date: Mon Nov 12 08:05:43 2018

Report memory reductions because of oom intervention

This CL adds new UMAs that report the amount of memory metrics that's reduced as a result of
intervention.

Bug: 888935
Change-Id: Ie336559f2046f0929830df7bf3b2d35ce7887423
Reviewed-on: https://chromium-review.googlesource.com/c/1319399
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Yuzu Saijo <yuzus@chromium.org>
Cr-Commit-Position: refs/heads/master@{#607169}
[modify] https://crrev.com/60addda9a6277ea88d60df67bc5a51cc90477233/third_party/blink/renderer/controller/oom_intervention_impl.cc
[modify] https://crrev.com/60addda9a6277ea88d60df67bc5a51cc90477233/third_party/blink/renderer/controller/oom_intervention_impl.h
[modify] https://crrev.com/60addda9a6277ea88d60df67bc5a51cc90477233/tools/metrics/histograms/histograms.xml