Allow profile owners to set the unknown source setting

This allows work profile MDM to enable unknown sources
even if the user doesn't have UI for it. Installing an
app from an unknown source will still prompt the user
with the package installer dialog, so it's not like the
MDM can now quietly install apps from non-market sources.

Bug: 18316350

Change-Id: Ia8f4fe36f12a258aa888e085acc0b358925f4817

core/java/android/app/admin/DevicePolicyManager.java

@@ -3306,6 +3306,7 @@ public class DevicePolicyManager {
      * <p>The settings that can be updated by a profile or device owner with this method are:
      * <ul>
      * <li>{@link Settings.Secure#DEFAULT_INPUT_METHOD}</li>
+     * <li>{@link Settings.Secure#INSTALL_NON_MARKET_APPS}</li>
      * <li>{@link Settings.Secure#SKIP_FIRST_USE_HINTS}</li>
      * </ul>
      * <p>A device owner can additionally update the following settings:

services/devicepolicy/java/com/android/server/devicepolicy/DevicePolicyManagerService.java

@@ -179,6 +179,7 @@ public class DevicePolicyManagerService extends IDevicePolicyManager.Stub {
         SECURE_SETTINGS_WHITELIST = new HashSet();
         SECURE_SETTINGS_WHITELIST.add(Settings.Secure.DEFAULT_INPUT_METHOD);
         SECURE_SETTINGS_WHITELIST.add(Settings.Secure.SKIP_FIRST_USE_HINTS);
+        SECURE_SETTINGS_WHITELIST.add(Settings.Secure.INSTALL_NON_MARKET_APPS);
 
         SECURE_SETTINGS_DEVICEOWNER_WHITELIST = new HashSet();
         SECURE_SETTINGS_DEVICEOWNER_WHITELIST.addAll(SECURE_SETTINGS_WHITELIST);