The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/1a867255fe4aa1f86136315520a26cfa44f9515e

commit 1a867255fe4aa1f86136315520a26cfa44f9515e
Author: rajendrant <rajendrant@chromium.org>
Date: Thu Jun 09 00:08:51 2016

Record precache periodic task interval

Precache periodic task is invoked by GCMNetworkManager when the
conditions are right for precaching. The interval between successive
task invocations should be logged.

BUG= 618386 

Review-Url: https://codereview.chromium.org/2047573007
Cr-Commit-Position: refs/heads/master@{#398743}

[modify] https://crrev.com/1a867255fe4aa1f86136315520a26cfa44f9515e/chrome/android/java/src/org/chromium/chrome/browser/precache/PrecacheController.java
[modify] https://crrev.com/1a867255fe4aa1f86136315520a26cfa44f9515e/tools/metrics/histograms/histograms.xml