Fix label for a11y VoiceOver

Fix label for a11y VoiceOver

Made the 'entry-box' label into a div.
Made the 'time' div into a label and assigned it for the checkbox.
Updated the code that selects the checkbox to prevent introduction of bug
where clicking the row would not toggle the checkbox.

VoiceOver after change:
checkbox: "<history item timestamp> <checked/unchecked> checkbox"
url: "visited link <name of link>"
drop down: "actions pop up button"

The exact words will be different depending on TTS program used,
but should be similar for the controls in the list.

There are no tests uploaded because these changes rely on VoiceOver to validate.

BUG=404870
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=291274

[Dan Beam, 2014-08-21 21:03:43]

lgtm

[hcarmona, 2014-08-21 21:05:25]

The CQ bit was checked by hcarmona@chromium.org

[Dan Beam, 2014-08-21 21:07:01]

slgtm can you update this comment separately?

chrome/browser/resources/history/history.js:2098: * Handle click event for
entryBox labels.

[commit-bot: I haz the power, 2014-08-21 21:13:07]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/hcarmona@chromium.org/492083002/1

[commit-bot: I haz the power, 2014-08-22 00:40:06]

Committed patchset #1 (1) as 291274