Disable next compatibility mode for ChromeVox on dev channel

chrome/renderer/resources/extensions/automation/automation_node.js

 // Copyright 2014 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 AutomationEvent = require('automationEvent').AutomationEvent;
 var automationInternal =
     require('binding').Binding.create('automationInternal').generate();
 var exceptionHandler = require('uncaught_exception_handler');
 var IsInteractPermitted =
     requireNative('automationInternal').IsInteractPermitted;
@@ skipping 932 matching lines @@
     var result = GetRootID(this.treeID);
 
     // Don't return undefined, because the id is often passed directly
     // as an argument to a native binding that expects only a valid number.
     if (result === undefined)
       return -1;
 
     return result;
   },
 
+  get chromeChannel() {
+    return GetStringAttribute(this.treeID, this.id, 'chromeChannel');
+  },
+
   get docUrl() {
     return GetDocURL(this.treeID);
   },
 
   get docTitle() {
     return GetDocTitle(this.treeID);
   },
 
   get docLoaded() {
     return GetDocLoaded(this.treeID);
@@ skipping 155 matching lines @@
       'htmlAttributes',
   ]),
 });
 
 function AutomationRootNode() {
   privates(AutomationRootNode).constructPrivate(this, arguments);
 }
 utils.expose(AutomationRootNode, AutomationRootNodeImpl, {
   superclass: AutomationNode,
   readonly: [
+    'chromeChannel',
     'docTitle',
     'docUrl',
     'docLoaded',
     'docLoadingProgress',
     'anchorObject',
     'anchorOffset',
     'anchorAffinity',
     'focusObject',
     'focusOffset',
     'focusAffinity',
   ],
 });
 
 utils.defineProperty(AutomationRootNode, 'get', function(treeID) {
   return AutomationRootNodeImpl.get(treeID);
 });
 
 utils.defineProperty(AutomationRootNode, 'getOrCreate', function(treeID) {
   return AutomationRootNodeImpl.getOrCreate(treeID);
 });
 
 utils.defineProperty(AutomationRootNode, 'destroy', function(treeID) {
   AutomationRootNodeImpl.destroy(treeID);
 });
 
 exports.$set('AutomationNode', AutomationNode);
 exports.$set('AutomationRootNode', AutomationRootNode);