Add a comment to fast/forms/select/optgroup-clicking.html about a failure on OSX.

Add a comment to fast/forms/select/optgroup-clicking.html about a failure on OSX.

It's an expected behavior.

BUG=234018
Committed: https://crrev.com/221ab82ebc9c347dedc6a5575616ea4066047191
Cr-Commit-Position: refs/heads/master@{#355718}

[tkent, 2015-10-22 01:58:24]

tkent@chromium.org changed reviewers:
+ keishi@chromium.org

[tkent, 2015-10-22 01:58:24]

Keishi, please review this.

[keishi, 2015-10-23 02:21:12]

LGTM

[tkent, 2015-10-23 02:32:02]

The CQ bit was checked by tkent@chromium.org

[commit-bot: I haz the power, 2015-10-23 02:32:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1407053004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1407053004/1

[commit-bot: I haz the power, 2015-10-23 03:06:47]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-23 03:07:51]

Patchset 1 (id:??) landed as
https://crrev.com/221ab82ebc9c347dedc6a5575616ea4066047191
Cr-Commit-Position: refs/heads/master@{#355718}