Create Work Challenge per-user condition

Change the current static condition to a per-user condition so we
can check and enable/disable the work challenge properly. Also add
an isAllowed API, as the Work Challenge can only be used when the
user's DPC targets N or above to maintain backwards compatibility.

Change-Id: I0cb8b475838816801868ffb24726407aa257b4de
diff --git a/core/java/android/app/admin/DevicePolicyManager.java b/core/java/android/app/admin/DevicePolicyManager.java
index 4de3ceb..bd0635d 100644
--- a/core/java/android/app/admin/DevicePolicyManager.java
+++ b/core/java/android/app/admin/DevicePolicyManager.java
@@ -941,6 +941,22 @@
     }
 
     /**
+     * Returns true if the Profile Challenge is available to use for the given profile user.
+     *
+     * @hide
+     */
+    public boolean isSeparateProfileChallengeAllowed(int userHandle) {
+        if (mService != null) {
+            try {
+                return mService.isSeparateProfileChallengeAllowed(userHandle);
+            } catch (RemoteException e) {
+                Log.w(TAG, REMOTE_EXCEPTION_MESSAGE, e);
+            }
+        }
+        return false;
+    }
+
+    /**
      * Constant for {@link #setPasswordQuality}: the policy has no requirements
      * for the password.  Note that quality constants are ordered so that higher
      * values are more restrictive.