Switch spelling marker from '_' to '#' in spellcheck_test

third_party/WebKit/LayoutTests/editing/spelling/spellcheck_test.js

 // Copyright 2016 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.
 
 'use strict';
 
 // This file provides
 // |spellcheck_test(sample, tester, expectedText, opt_title)| asynchronous test
 // to W3C test harness for easier writing of spellchecker test cases.
 //
@@ skipping 272 matching lines @@
  * @param {number} retryInterval
  */
 function verifyMarkers(
     testObject, sample, expectedText, remainingRetry, retryInterval) {
   assert_not_equals(
       window.internals, undefined,
       'window.internals is required for running automated spellcheck tests.');
 
   /** @type {!MarkerSerializer} */
   const serializer = new MarkerSerializer({
-    spelling: '_',
+    spelling: '#',
     grammar: '~'});
 
   try {
     assert_equals(serializer.serialize(sample.document), expectedText);
     testObject.done();
   } catch (error) {
     if (remainingRetry <= 0)
       throw error;
 
     // Force invoking idle time spellchecker in case it has not been run yet.
@@ skipping 124 matching lines @@
         expectedText: expectedText, args: args});
     return;
   }
 
   invokeSpellcheckTest(input, tester, expectedText, args);
 }
 
 // Export symbols
 window.spellcheck_test = spellcheckTest;
 })();