Only enable multi-user settings if a secure settings flag is set

Use a secure settings key of "multiuser_enabled" that can be
set to "1" to enable the multiuser panel in Settings.

Change-Id: I37d96f6055bc7f87ef271ebdc58f16e7dcecca7b
diff --git a/src/com/android/settings/Settings.java b/src/com/android/settings/Settings.java
index 7e4e725..3513dcc 100644
--- a/src/com/android/settings/Settings.java
+++ b/src/com/android/settings/Settings.java
@@ -89,6 +89,8 @@
             R.id.about_settings
     };
 
+    private boolean mEnableUserManagement = false;
+
     // TODO: Update Call Settings based on airplane mode state.
 
     protected HashMap<Integer, Integer> mHeaderIndexMap = new HashMap<Integer, Integer>();
@@ -100,6 +102,11 @@
             getWindow().setUiOptions(0);
         }
 
+        if (android.provider.Settings.Secure.getInt(getContentResolver(), "multiuser_enabled", -1)
+                > 0) {
+            mEnableUserManagement = true;
+        }
+
         getMetaData();
         mInLocalHeaderSwitch = true;
         super.onCreate(savedInstanceState);
@@ -351,7 +358,8 @@
                     target.remove(header);
                 }
             } else if (id == R.id.user_settings) {
-                if (!UserId.MU_ENABLED || UserId.myUserId() != 0
+                if (!mEnableUserManagement
+                        || !UserId.MU_ENABLED || UserId.myUserId() != 0
                         || !getResources().getBoolean(R.bool.enable_user_management)
                         || Utils.isMonkeyRunning()) {
                     target.remove(header);