Parse meta tag that disables ChromeVox content script and forces compat mode.

chrome/browser/resources/chromeos/chromevox/chromevox/injected/externs.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.
 
 /**
  * External functions for MathJax bridge.
  * @typedef {Object}
  */
 function MathJax() {}
 
@@ skipping 195 matching lines @@
  * Each text box has a bounding box (left, top, width, height) and
  * each of these contains an array of nodes of type 'text' or 'url'.
  * @type {Array<
  *           {left: number, top: number, width: number, height: number,
  *            textNodes: Array<
  *                {type: string, text: string, url: string}>
  *           }>
  *       }
  */
 PDFAccessibilityJSONReply.prototype.textBox;
+
+
+/**
+ * @param {?function(this:S, T, number, !Array<T>): ?} callback
+ * @param {S=} opt_thisobj
+ * @this {{length: number}|Array<T>}
+ * @template T,S
+ */
+NodeList.prototype.forEach = function(callback, opt_thisobj) {};