Finish implementing ChromeVox Next active indicator.

chrome/browser/resources/chromeos/chromevox/cvox2/background/base_automation_handler.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 Basic facillities to handle events from a single automation
  * node.
  */
 
 goog.provide('BaseAutomationHandler');
@@ skipping 17 matching lines @@
    * Maps an automation event to its listener.
    * @type {!Object<EventType, function(Object) : void>}
    */
   this.listenerMap_ = {
     alert: this.onAlert,
     focus: this.onFocus,
     hover: this.onEventDefault,
     loadComplete: this.onLoadComplete,
     menuStart: this.onEventDefault,
     menuEnd: this.onEventDefault,
+    scrollPositionChanged: this.onScrollPositionChanged,
     textChanged: this.onTextOrTextSelectionChanged,
     textSelectionChanged: this.onTextOrTextSelectionChanged,
     valueChanged: this.onValueChanged
   };
 
   /** @type {!Object<string, function(AutomationEvent): void>} @private */
   this.listeners_ = {};
 
   this.register_();
 };
@@ skipping 59 matching lines @@
 
   /**
    * @param {Object} evt
    */
   onFocus: function(evt) {},
 
   /**
    * @param {Object} evt
    */
   onLoadComplete: function(evt) {},
+
+  /**
+   * @param {Object} evt
+   */
   onEventDefault: function(evt) {},
 
   /**
    * @param {Object} evt
    */
+  onScrollPositionChanged: function(evt) {},
+
+  /**
+   * @param {Object} evt
+   */
   onTextOrTextSelectionChanged: function(evt) {},
 
   /**
    * @param {Object} evt
    */
   onValueChanged: function(evt) {}
 };
 
 });  // goog.scope