[Downloads UI] Add null checks to prevent crash when selecting deleted items

[Downloads UI] Add null checks to prevent crash when selecting deleted items

If you move quickly enough, it's possible to select an item that was just
deleted then choose to delete it again. Add some null checks to prevent
a crash.

BUG=652176
Committed: https://crrev.com/484d6ab408cd722254b9e80757558ae3948a1721
Cr-Commit-Position: refs/heads/master@{#422662}

[Theresa, 2016-10-03 22:53:53]

The CQ bit was checked by twellington@chromium.org to run a CQ dry run

[Theresa, 2016-10-03 22:54:16]

twellington@chromium.org changed reviewers:
+ dfalcantara@chromium.org

[Theresa, 2016-10-03 22:54:17]

ptal

[commit-bot: I haz the power, 2016-10-03 22:54:42]

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

[gone, 2016-10-04 00:21:12]

lgtm

[Theresa, 2016-10-04 00:30:16]

The CQ bit was unchecked by twellington@chromium.org

[Theresa, 2016-10-04 00:30:16]

The CQ bit was checked by twellington@chromium.org

[commit-bot: I haz the power, 2016-10-04 00:30:53]

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, 2016-10-04 01:54:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-04 01:56:39]

Description was changed from

==========
[Downloads UI] Add null checks to prevent crash when selecting deleted items

If you move quickly enough, it's possible to select an item that was just
deleted then choose to delete it again. Add some null checks to prevent
a crash.

BUG=652176
==========

to

==========
[Downloads UI] Add null checks to prevent crash when selecting deleted items

If you move quickly enough, it's possible to select an item that was just
deleted then choose to delete it again. Add some null checks to prevent
a crash.

BUG=652176

Committed: https://crrev.com/484d6ab408cd722254b9e80757558ae3948a1721
Cr-Commit-Position: refs/heads/master@{#422662}
==========

[commit-bot: I haz the power, 2016-10-04 01:56:40]

Patchset 1 (id:??) landed as
https://crrev.com/484d6ab408cd722254b9e80757558ae3948a1721
Cr-Commit-Position: refs/heads/master@{#422662}