Update the usage of locknow in testdpc

Change-Id: I8dc17569d5d03a6ee7a30409a3778a1871717f11
Fix: 29379761

Author: tony-mak

app/src/main/java/com/afwsamples/testdpc/policy/PolicyManagementFragment.java

@@ -501,7 +501,7 @@ public void onPositiveButtonClicked(String[] lockTaskArray) {
                 showResetPasswordPrompt();
                 return false;
             case LOCK_NOW_KEY:
-                mDevicePolicyManager.lockNow();
+                lockNow();
                 return true;
             case START_LOCK_TASK:
                 getActivity().startLockTask();
@@ -695,6 +695,19 @@ public void onPositiveButtonClicked(String[] lockTaskArray) {
         return false;
     }
 
+    @TargetApi(Build.VERSION_CODES.N)
+    private void lockNow() {
+        if (Util.isBeforeN() || !Util.isManagedProfile(getActivity(), mAdminComponentName)) {
+            mDevicePolicyManager.lockNow();
+        } else {
+            // In N for work profiles we should call lockNow on the parent instance to
+            // lock the device.
+            DevicePolicyManager parentDpm
+                    = mDevicePolicyManager.getParentProfileInstance(mAdminComponentName);
+            parentDpm.lockNow();
+        }
+    }
+
     @Override
     @SuppressLint("NewApi")
     public boolean onPreferenceChange(Preference preference, Object newValue) {