mac: Fix StatusBubbleMacTest on OSX 10.10.

mac: Fix StatusBubbleMacTest on OSX 10.10.

The test relied on implicit assumptions about the system font. The system font
changed in OSX 10.10. I changed the test to always use a fixed font.

BUG=390276
Committed: https://crrev.com/cc4cd11dc4f9419888190c04dea388c00b1487f2
Cr-Commit-Position: refs/heads/master@{#296616}

[erikchen, 2014-09-23 22:30:46]

erikchen@chromium.org changed reviewers:
+ avi@chromium.org

[erikchen, 2014-09-23 22:30:47]

avi: Please review.

[Avi (use Gerrit), 2014-09-23 23:15:54]

lgtm

[erikchen, 2014-09-25 00:18:42]

I've tested that this test works on all OSX versions. (10.6 through 10.10)

[erikchen, 2014-09-25 00:18:46]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2014-09-25 00:20:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/595053002/1

[commit-bot: I haz the power, 2014-09-25 01:47:00]

Committed patchset #1 (id:1) as dc9263bb846cd580dee5d87ecea8e3e9d5a14f54

[commit-bot: I haz the power, 2014-09-25 01:47:56]

Patchset 1 (id:??) landed as
https://crrev.com/cc4cd11dc4f9419888190c04dea388c00b1487f2
Cr-Commit-Position: refs/heads/master@{#296616}

[erikchen, 2014-10-15 22:19:38]

Patchset #2 (id:20001) has been deleted