sys user split: first pass updating Settings

Update various places in Settings to use "admin" ueser flag
instead of checking user id "0".  This should be no-op in
single user mode since the only admin user would be user 0.
In split system user mode, this will correctly ACL admin
user instead of non-interactive system user.

Bug: 19913735
Change-Id: Ida4d59c5f689ea0dc34b3b3ff0822b087fa0afd6

src/com/android/settings/MasterClear.java

@@ -281,9 +281,9 @@ public class MasterClear extends InstrumentedFragment {
     @Override
     public View onCreateView(LayoutInflater inflater, ViewGroup container,
             Bundle savedInstanceState) {
-        if (!Process.myUserHandle().isOwner()
-                || UserManager.get(getActivity()).hasUserRestriction(
-                UserManager.DISALLOW_FACTORY_RESET)) {
+        final UserManager um = UserManager.get(getActivity());
+        if (!um.isAdminUser()
+                || um.hasUserRestriction(UserManager.DISALLOW_FACTORY_RESET)) {
             return inflater.inflate(R.layout.master_clear_disallowed_screen, null);
         }