Fix really dumb mistake in Mac accessibility.

Fix really dumb mistake in Mac accessibility.

Missing braces when adding code inside an "if" block,
resulting in lots of attributes being marked as editable
when they shouldn't be, breaking VoiceOver.

Regression happened in:
https://crrev.com/6185ca046850b24b92a5dffd9ab7d1ecc3048001
https://codereview.chromium.org/1435113003/

BUG=559210, 473220
Committed: https://crrev.com/a9a175a4c93023a84d52814c973520d15617dbe6
Cr-Commit-Position: refs/heads/master@{#361235}

[dmazzoni, 2015-11-23 23:36:45]

dmazzoni@chromium.org changed reviewers:
+ aboxhall@chromium.org

[aboxhall, 2015-11-24 00:37:02]

lgtm

[dmazzoni, 2015-11-24 00:42:05]

The CQ bit was checked by dmazzoni@chromium.org

[commit-bot: I haz the power, 2015-11-24 00:43:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1473483002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1473483002/1

[commit-bot: I haz the power, 2015-11-24 02:29:15]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-24 02:30:44]

Patchset 1 (id:??) landed as
https://crrev.com/a9a175a4c93023a84d52814c973520d15617dbe6
Cr-Commit-Position: refs/heads/master@{#361235}