Selection API: Do not change focus by Selection functions.

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 304 matching lines @@
     // something in JavaScript (e.g., a |Promise|), so that we can actively
     // know the completion of spellchecking instead of passively waiting for
     // markers to appear or disappear.
     testObject.step_timeout(
         () => verifyMarkers(testObject, sample, expectedText,
                             remainingRetry - 1, retryInterval),
         retryInterval);
   }
 }
 
+function focusNearestAncestorOfAnchor(selection) {
+  for (var anchor = selection.anchorNode; anchor; anchor = anchor.parentNode) {
+    if (anchor.nodeType != Node.ELEMENT_NODE)
+      continue;
+    anchor.focus();
+    if (anchor.ownerDocument.activeElement == anchor)
+      return;
+  }
+}
+
 // Spellchecker gets triggered not only by text and selection change, but also
 // by focus change. For example, misspelling markers in <INPUT> disappear when
 // the window loses focus, even though the selection does not change.
 // Therefore, we disallow spellcheck tests from running simultaneously to
 // prevent interference among them. If we call spellcheck_test while another
 // test is running, the new test will be added into testQueue waiting for the
 // completion of the previous test.
 
 /** @type {boolean} */
 var spellcheckTestRunning = false;
 /** @type {!Array<!Object>} */
 const testQueue = [];
 
 /**
  * @param {!Test} testObject
  * @param {!Sample|string} input
  * @param {function(!Document)|string} tester
  * @param {string} expectedText
  */
 function invokeSpellcheckTest(testObject, input, tester, expectedText) {
   spellcheckTestRunning = true;
 
   testObject.step(() => {
     // TODO(xiaochengh): Merge the following part with |assert_selection|.
     /** @type {!Sample} */
     const sample = typeof(input) === 'string' ? new Sample(input) : input;
     testObject.sample = sample;
+    focusNearestAncestorOfAnchor(sample.selection);
 
     if (typeof(tester) === 'function') {
       tester.call(window, sample.document);
     } else if (typeof(tester) === 'string') {
       const strings = tester.split(/ (.+)/);
       sample.document.execCommand(strings[0], false, strings[1]);
     } else {
       assert_unreached(`Invalid tester: ${tester}`);
     }
 
@@ skipping 84 matching lines @@
         tester: tester, expectedText: expectedText});
     return;
   }
 
   invokeSpellcheckTest(testObject, input, tester, expectedText);
 }
 
 // Export symbols
 window.spellcheck_test = spellcheckTest;
 })();