This still needs to be done. My apologies for never getting around to it.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/0ac3ad8c6df8a6d86eb6d152895592894a18fc65

commit 0ac3ad8c6df8a6d86eb6d152895592894a18fc65
Author: Marc Treib <treib@chromium.org>
Date: Thu Mar 15 16:11:28 2018

Refactor about_sync_util.cc to remove unsafe usage of raw pointers

The previous [Bool|Int|String]SyncStat classes relied on raw pointers
into base::ListValue, which is bad because they become invalid when
the actual std::vector backing the list gets resized. They're replaced
by new SectionList/Section/Stat classes that are less fragile.
While we're here, this also updates the code to use the new base::Value
APIs, i.e. using values instead of unique_ptrs.

Bug:  702230 
Change-Id: I5da50857587acb50ffb8849a7fa2cf8dabce9e45
Reviewed-on: https://chromium-review.googlesource.com/955324
Commit-Queue: Marc Treib <treib@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543384}
[modify] https://crrev.com/0ac3ad8c6df8a6d86eb6d152895592894a18fc65/components/sync/driver/about_sync_util.cc