Fix memory leak in NotificationProviderApiTest.Events.

Fix memory leak in NotificationProviderApiTest.Events.

This new test had a memory leak as reported by Linux ASan LSan:

http://build.chromium.org/p/chromium.memory/builders/Linux%20ASan%20LSan%20Tests%20%281%29/builds/4540/steps/browser_tests/logs/Events

TBR=kalman@chromium.org, liyanhou@chromium.org
BUG=397197
NOTREECHECKS=true
NOTRY=true

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=287170

[pneubeck (no reviews), 2014-08-02 07:09:28]

The CQ bit was checked by pneubeck@chromium.org

[pneubeck (no reviews), 2014-08-02 07:09:35]

The CQ bit was unchecked by pneubeck@chromium.org

[pneubeck (no reviews), 2014-08-02 07:21:49]

The CQ bit was checked by pneubeck@chromium.org

[commit-bot: I haz the power, 2014-08-02 07:23:28]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/pneubeck@chromium.org/433073003/20001

[pneubeck (no reviews), 2014-08-02 07:26:39]

The CQ bit was unchecked by pneubeck@chromium.org

[pneubeck (no reviews), 2014-08-02 07:26:44]

The CQ bit was checked by pneubeck@chromium.org

[commit-bot: I haz the power, 2014-08-02 07:28:50]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/pneubeck@chromium.org/433073003/20001

[commit-bot: I haz the power, 2014-08-02 07:30:35]

Change committed as 287170