history: break <label> relationship between time and delete checkbox.

history: break <label> relationship between time and delete checkbox.

Clicking anywhere in an entry already toggles the checkbox and this was
just messing up VoiceOver spoken feedback.

Also add aria-label to satisfy a11y audit and make voice feedback better.

R=dmazzoni@chromium.org
BUG=385344
Committed: https://crrev.com/54249ff53efa22453631d45b55da7dd744cac78e
Cr-Commit-Position: refs/heads/master@{#300282}

[Dan Beam, 2014-10-18 02:56:55]

dbeam@chromium.org changed required reviewers:
+ dmazzoni@chromium.org

[dmazzoni, 2014-10-20 16:30:01]

The CQ bit was checked by dmazzoni@chromium.org

[dmazzoni, 2014-10-20 16:30:01]

lgtm

[commit-bot: I haz the power, 2014-10-20 16:30:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/661043006/20001

[commit-bot: I haz the power, 2014-10-20 17:03:12]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2014-10-20 17:04:03]

Patchset 2 (id:??) landed as
https://crrev.com/54249ff53efa22453631d45b55da7dd744cac78e
Cr-Commit-Position: refs/heads/master@{#300282}