Complete live region support in ChromeVox Next.

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.
+ */
+
+goog.provide('ChromeVoxMode');
+goog.provide('ChromeVoxState');
+
+goog.require('cursors.Cursor');
+
+/**
+ * All possible modes ChromeVox can run.
+ * @enum {string}
+ */
+ChromeVoxMode = {
+  CLASSIC: 'classic',
+  COMPAT: 'compat',
+  NEXT: 'next',
+  FORCE_NEXT: 'force_next'
+};
+
+/**
+ * ChromeVox2 state object.
+ * @constructor
+ */
+ChromeVoxState = function() {
+  if (ChromeVoxState.instance)
+    throw 'Trying to create two instances of singleton ChromeVoxState.';
+  ChromeVoxState.instance = this;
+};
+
+/**
+ * @type {ChromeVoxState}
+ */
+ChromeVoxState.instance;
+
+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: function(mode, opt_injectClassic) {
+    throw new Error('setMode must be implemented by subclass.');
+  },
+
+  /**
+   * Refreshes the current mode based on a url.
+   * @param {string} url
+   */
+  refreshMode: function(url) {
+    throw new Error('refresthMode must be implemented by subclass.');
+  },
+
+  /** @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: function(newRange) {
+    throw new Error('setCurrentRange must be implemented by subclass.');
+  },
+};