Refactored device_management_service.cc to avoid using BrowserThread and g_browser_process.

BUG=271392

Review URL: https://chromiumcodereview.appspot.com/23182004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224829 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224829
Disable notifications by default on Windows

Set the default value of notifications_enabled to false on Windows so that users
don't see a firewall message when they open Chrome.

BUG=297208
R=vitalybuka@chromium.org

Review URL: https://codereview.chromium.org/24358004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@224830 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 224830