Block user from setting safe boot setting via adb

Bug: 29900345
Change-Id: Id3b4472b59ded2c7c29762ddf008ee8486009dbb
diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
index 5c72215..90eade4 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
@@ -1202,6 +1202,11 @@
                 restriction = UserManager.DISALLOW_CONFIG_VPN;
                 break;
 
+            case Settings.Global.SAFE_BOOT_DISALLOWED:
+                if ("1".equals(value)) return false;
+                restriction = UserManager.DISALLOW_SAFE_BOOT;
+                break;
+
             default:
                 if (setting != null && setting.startsWith(Settings.Global.DATA_ROAMING)) {
                     if ("0".equals(value)) return false;