Revert of Make ChromeVox Next a setting in options page.

chrome/browser/resources/chromeos/chromevox/cvox2/background/chromevox_state.js

 // Copyright 2015 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.
 
 /**
  * @fileoverview An interface for querying and modifying the global
  *     ChromeVox state, to avoid direct dependencies on the Background
  *     object and to facilitate mocking for tests.
  */
 
@@ skipping 21 matching lines @@
   if (ChromeVoxState.instance)
     throw 'Trying to create two instances of singleton ChromeVoxState.';
   ChromeVoxState.instance = this;
 };
 
 /**
  * @type {ChromeVoxState}
  */
 ChromeVoxState.instance;
 
-/**
- * Holds the un-composite tts object.
- * @type {Object}
- */
-ChromeVoxState.backgroundTts;
-
-/**
- * @type {boolean}
-  */
-  ChromeVoxState.isReadingContinuously;
-
 ChromeVoxState.prototype = {
   /** @type {ChromeVoxMode} */
   get mode() {
     return this.getMode();
   },
 
   /**
    * @return {ChromeVoxMode} The current mode.
    * @protected
    */
   getMode: function() {
     return ChromeVoxMode.NEXT;
   },
 
+  /**
+   * Sets the current ChromeVox mode.
+   * @param {ChromeVoxMode} mode
+   * @param {boolean=} opt_injectClassic Injects ChromeVox classic into tabs;
+   *                                     defaults to false.
+   */
+  setMode: goog.abstractMethod,
+
+  /**
+   * Refreshes the current mode based on a node.
+   * @param {!chrome.automation.AutomationNode} url
+   */
+  refreshMode: goog.abstractMethod,
+
   /** @type {cursors.Range} */
   get currentRange() {
     return this.getCurrentRange();
   },
 
   /**
    * @return {cursors.Range} The current range.
    * @protected
    */
   getCurrentRange: function() {
     return null;
   },
 
   /**
    * @param {cursors.Range} newRange The new range.
    */
   setCurrentRange: goog.abstractMethod,
 };