ui: message_center and app_list tests opt into real GL NullDraw contexts

ui: message_center and app_list tests opt into real GL NullDraw contexts

This breaks the dependency on the TestCompositor for
these test suites. Once it's no longer in use by any test
suite, we can remove it.

These tests only compile in the compositor and ui/gl/ on non-Mac
platforms, so only initialize GL there.

Depends on: https://codereview.chromium.org/175093004/

R=ben@chromium.org
BUG=270918
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=252771

[danakj, 2014-02-21 21:29:16]

The CQ bit was checked by danakj@chromium.org

[danakj, 2014-02-21 21:29:16]

The CQ bit was unchecked by danakj@chromium.org

[Ben Goodger (Google), 2014-02-21 21:32:12]

lgtm

[danakj, 2014-02-21 21:37:05]

The CQ bit was checked by danakj@chromium.org

[commit-bot: I haz the power, 2014-02-21 21:37:52]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/danakj@chromium.org/168193003/10009

[commit-bot: I haz the power, 2014-02-21 23:41:15]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-02-21 23:41:17]

Retried try job too often on win_rel for step(s) unit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=win_rel&nu...

[danakj, 2014-02-21 23:46:37]

The CQ bit was checked by danakj@chromium.org

[commit-bot: I haz the power, 2014-02-21 23:48:20]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/danakj@chromium.org/168193003/10009

[commit-bot: I haz the power, 2014-02-22 01:28:29]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/danakj@chromium.org/168193003/10009

[commit-bot: I haz the power, 2014-02-22 08:09:19]

Change committed as 252771