Add chrome.screenlockPrivate API functions to handle alternate auth types.

chrome/test/data/extensions/api_test/screenlockPrivate/test.js

-// Copyright 2013 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-var stage = 0;
-
-function step() {
-  chrome.screenlockPrivate.getLocked(function gotLocked(locked) {
-    if (stage === 0) {
-      if (locked) {
-        chrome.test.fail('locked at stage ' + stage);
-      } else {
-        chrome.screenlockPrivate.setLocked(true);
-        ++stage;
-        return true;
-      }
-    } else if (stage === 1) {
-      if (!locked) {
-        chrome.test.fail('unlocked at stage ' + stage);
-      } else {
-        chrome.screenlockPrivate.setLocked(false);
-        ++stage;
-        return true;
-      }
-    } else if (stage === 2) {
-      if (locked) {
-        chrome.test.fail('locked at stage ' + stage);
-      } else {
-        chrome.test.succeed();
-      }
-    }
-  });
-};
-
-chrome.screenlockPrivate.onChanged.addListener(function(locked) {
-  if (locked != (1 == (stage % 2))) {
-    chrome.test.fail((locked ? '' : 'un') + 'locked at stage ' + stage +
-                     ' onChanged');
-  } else {
-    return step();
-  }
-});
-
-step();