Fix DCHECK in ReadingListEntry.

Fix DCHECK in ReadingListEntry.

If an entry has been stored in a previous version of Chrome, the
update_title_time_us field can be 0.
The DCHECK works for new entries, but not for old ones.

BUG=705544
Review-Url: https://codereview.chromium.org/2774393002
Cr-Commit-Position: refs/heads/master@{#460098}
Committed: https://chromium.googlesource.com/chromium/src/+/0db8adf280d1833ce081e80ad0e9c8b5c44c4e4c

[Olivier, 2017-03-27 16:53:17]

olivierrobin@chromium.org changed reviewers:
+ jif@chromium.org

[jif, 2017-03-28 09:24:01]

The new comments will add unnecessary mental overhead for as long as this code
is in Chromium. So surely a long time.

Could we add a TODO to revert this CL in a couple chrome versions?

[Olivier, 2017-03-28 11:04:14]

On 2017/03/28 09:24:01, jif wrote:
> The new comments will add unnecessary mental overhead for as long as this code
> is in Chromium. So surely a long time.
> 
> Could we add a TODO to revert this CL in a couple chrome versions?

Removing it would make all device inconsistent if a single one sync an entry
with 0 title update time.
Not sure we want that.

[jif, 2017-03-28 12:13:49]

lgtm

[Olivier, 2017-03-28 13:29:20]

The CQ bit was checked by olivierrobin@chromium.org

[commit-bot: I haz the power, 2017-03-28 13:29:38]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-03-28 14:24:23]

CQ is committing da patch.

Bot data: {"patchset_id": 20001, "attempt_start_ts": 1490707760962030,
"parent_rev": "29f372aa0cdb9b2b6cca4f8bf4297ee9d126c16d", "commit_rev":
"0db8adf280d1833ce081e80ad0e9c8b5c44c4e4c"}

[commit-bot: I haz the power, 2017-03-28 14:25:07]

Description was changed from

==========
Fix DCHECK in ReadingListEntry.

If an entry has been stored in a previous version of Chrome, the
update_title_time_us field can be 0.
The DCHECK works for new entries, but not for old ones.

BUG=705544
==========

to

==========
Fix DCHECK in ReadingListEntry.

If an entry has been stored in a previous version of Chrome, the
update_title_time_us field can be 0.
The DCHECK works for new entries, but not for old ones.

BUG=705544

Review-Url: https://codereview.chromium.org/2774393002
Cr-Commit-Position: refs/heads/master@{#460098}
Committed:
https://chromium.googlesource.com/chromium/src/+/0db8adf280d1833ce081e80ad0e9...
==========

[commit-bot: I haz the power, 2017-03-28 14:25:08]

Committed patchset #2 (id:20001) as
https://chromium.googlesource.com/chromium/src/+/0db8adf280d1833ce081e80ad0e9...