Revert 221410 "Add ManagedUserSettingsService and a SupervisedUs..."
Broke Linux ChromiumOS Tests (1):
http://build.chromium.org/p/chromium.chromiumos/buildstatus?builder=Linux%20ChromiumOS%20Tests%20%281%29&number=32217
> Add ManagedUserSettingsService and a SupervisedUserPrefStore using it.
>
> BUG=280674
>
> Review URL: https://chromiumcodereview.appspot.com/
23466004
TBR=bauerb@chromium.org
Review URL: https://codereview.chromium.org/
23477040
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221411 0039d316-1c4b-4281-b951-d872f2087c98