Wire up an api to darken screen for accessibility

third_party/closure_compiler/externs/accessibility_private.js

-// Copyright 2016 The Chromium Authors. All rights reserved.
+// Copyright 2017 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.
 
 // This file was generated by:
 //   tools/json_schema_compiler/compiler.py.
 // NOTE: The format of types has changed. 'FooType' is now
 //   'chrome.accessibilityPrivate.FooType'.
 // Please run the closure compiler before committing changes.
 // See https://chromium.googlesource.com/chromium/src/+/master/docs/closure_compilation.md
 
@@ skipping 74 matching lines @@
  *     false to stop listening to events. Note that there is only ever one
  *     extension listening to key events.
  * @param {boolean} capture True if key events should be swallowed natively and
  *     not propagated if preventDefault() gets called by the extension's
  *     background page.
  * @see https://developer.chrome.com/extensions/accessibilityPrivate#method-setKeyboardListener
  */
 chrome.accessibilityPrivate.setKeyboardListener = function(enabled, capture) {};
 
 /**
+ * Darkens or undarkens the screen.
+ * @param {boolean} enabled True to darken screen; false to undarken screen.
+ * @see https://developer.chrome.com/extensions/accessibilityPrivate#method-darkenScreen
+ */
+chrome.accessibilityPrivate.darkenScreen = function(enabled) {};
+
+/**
  * Fired whenever ChromeVox should output introduction.
  * @type {!ChromeEvent}
  * @see https://developer.chrome.com/extensions/accessibilityPrivate#event-onIntroduceChromeVox
  */
 chrome.accessibilityPrivate.onIntroduceChromeVox;
 
 /**
  * Fired when an accessibility gesture is detected by the touch exploration
  * controller.
  * @type {!ChromeEvent}
  * @see https://developer.chrome.com/extensions/accessibilityPrivate#event-onAccessibilityGesture
  */
 chrome.accessibilityPrivate.onAccessibilityGesture;