[Devtools] Fixed bug with _visibleColumns not set

[Devtools] Fixed bug with _visibleColumns not set

Fixes a bug where it was throwing an error if the filter changed
during the user looking at a request.

R=dgozman,lushnikov
BUG=657637
Committed: https://crrev.com/1261489527c9e5f0278925b90f9d6dbc90103d4e
Cr-Commit-Position: refs/heads/master@{#426370}

[allada, 2016-10-19 22:35:43]

PTL

[dgozman, 2016-10-19 22:37:45]

lgtm

[allada, 2016-10-19 23:29:59]

The CQ bit was checked by allada@chromium.org

[commit-bot: I haz the power, 2016-10-19 23:30:48]

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, 2016-10-20 01:44:55]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-10-21 13:14:24]

Description was changed from

==========
[Devtools] Fixed bug with _visibleColumns not set

Fixes a bug where it was throwing an error if the filter changed
during the user looking at a request.

R=dgozman,lushnikov
BUG=657637
==========

to

==========
[Devtools] Fixed bug with _visibleColumns not set

Fixes a bug where it was throwing an error if the filter changed
during the user looking at a request.

R=dgozman,lushnikov
BUG=657637

Committed: https://crrev.com/1261489527c9e5f0278925b90f9d6dbc90103d4e
Cr-Commit-Position: refs/heads/master@{#426370}
==========

[commit-bot: I haz the power, 2016-10-21 13:14:24]

Patchset 1 (id:??) landed as
https://crrev.com/1261489527c9e5f0278925b90f9d6dbc90103d4e
Cr-Commit-Position: refs/heads/master@{#426370}