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chromium/third_party/blink/web_tests/editing/undo/redo_correct_selection.html 

<!doctype html>
<script src="../../resources/testharness.js"></script>
<script src="../../resources/testharnessreport.js"></script>
<script src="../assert_selection.js"></script>
<script>
test(() => assert_selection(
  '<div contenteditable>^012<select></select>|</div><option></option>',
  selection => {
      const div = selection.document.querySelector('div');
      let currentCommand = '';
      function execCommand(name) {
        currentCommand = name;
        selection.document.execCommand(name);
      }
      // Move SELECT into OPTION before calling |FrameSelection::setSelection()|
      // in |Editor::reappliedEditing()|.
      div.addEventListener('input', () => {
        if (currentCommand !== 'redo')
          return;
        const div = selection.document.querySelector('div');
        const select = selection.document.querySelector('select');
        const option = selection.document.querySelector('option');
        option.appendChild(select);
      });
      execCommand('bold');
      execCommand('undo');
      execCommand('redo');
  },
  '<div contenteditable><b>^012|</b></div><option><select></select></option>'),
  'Redo command should update selection');
</script>