GitLab

This fixes a race condition which may cause notifications to not work
on startup.

This is a minimal change for ease of merging.  Unit tests will be landed
in a separate patch.

BUG=139424


Review URL: https://chromiumcodereview.appspot.com/10836002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@148907 0039d316-1c4b-4281-b951-d872f2087c98