Make HTML5 <mark> accessible.

chrome/common/extensions/api/automation.idl

 // 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.
 
 // The <code>chrome.automation</code> API allows developers to access the
 // automation (accessibility) tree for the browser. The tree resembles the DOM
 // tree, but only exposes the <em>semantic</em> structure of a page. It can be
 // used to programmatically interact with a page by examining names, roles, and
 // states, listening for events, and performing actions on nodes.
 [nocompile] namespace automation {
@@ skipping 96 matching lines @@
     lineBreak,
     link,
     listBoxOption,
     listBox,
     listItem,
     listMarker,
     list,
     locationBar,
     log,
     main,
+    mark,
     marquee,
     math,
     menuBar,
     menuButton,
     menuItem,
     menuItemCheckBox,
     menuItemRadio,
     menuListOption,
     menuListPopup,
     menu,
@@ skipping 428 matching lines @@
     // Add a tree change observer. Tree change observers are static/global, they
     // listen to changes across all trees.
     [nocompile] static void addTreeChangeObserver(
         TreeChangeObserver observer);
 
     // Remove a tree change observer.
     [nocompile] static void removeTreeChangeObserver(
         TreeChangeObserver observer);
   };
 };