📰 Fix crash when tapping the menu on closed NTP

[NTP Client] Fix crash when tapping the menu on closed NTP

Although the menu is supposed to be closed when we navigate away from
the NTP, we can crash because of race conditions. This CL adds back
checking that the view is attached.

BUG=668945
Committed: https://crrev.com/4daca6414728afe3edb8765634effaf113119004
Cr-Commit-Position: refs/heads/master@{#436626}

[dgn, 2016-12-06 15:36:51]

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

[commit-bot: I haz the power, 2016-12-06 15:37:06]

Dry run: 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, 2016-12-06 16:19:21]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-12-06 16:19:21]

Dry run: This issue passed the CQ dry run.

[dgn, 2016-12-06 16:34:20]

dgn@chromium.org changed reviewers:
+ bauerb@chromium.org

[dgn, 2016-12-06 16:34:20]

PTAL

[Bernhard Bauer, 2016-12-06 17:18:29]

lgtm

[dgn, 2016-12-06 17:22:34]

The CQ bit was checked by dgn@chromium.org

[commit-bot: I haz the power, 2016-12-06 17:23:08]

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, 2016-12-06 17:29:12]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1481044954597610, "parent_rev":
"a1b359ecf83626c78166e2723735b635f3a6889a", "commit_rev":
"1db34d0567839984835dc259ea40e44c2b722d8a"}

[commit-bot: I haz the power, 2016-12-06 17:29:36]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-12-06 17:32:25]

Description was changed from

==========
[NTP Client] Fix crash when tapping the menu on closed NTP

Although the menu is supposed to be closed when we navigate away from
the NTP, we can crash because of race conditions. This CL adds back
checking that the view is attached.

BUG=668945
==========

to

==========
[NTP Client] Fix crash when tapping the menu on closed NTP

Although the menu is supposed to be closed when we navigate away from
the NTP, we can crash because of race conditions. This CL adds back
checking that the view is attached.

BUG=668945

Committed: https://crrev.com/4daca6414728afe3edb8765634effaf113119004
Cr-Commit-Position: refs/heads/master@{#436626}
==========

[commit-bot: I haz the power, 2016-12-06 17:32:26]

Patchset 1 (id:??) landed as
https://crrev.com/4daca6414728afe3edb8765634effaf113119004
Cr-Commit-Position: refs/heads/master@{#436626}