function localSpellCheckingFunction(words, spellChecker, callback) {
  const len = words.length;
  const results = [];
  for (let i = 0; i < len; i++) {
    const word = words[i];
    let found = false;
    for (let j = 0; j < VOCABULARY.length; ++j) {
      if (VOCABULARY[j] == word) {
        found = true;
        break;
      }
    }
    if (found) {
      results.push([word, SpellCheck.WordStatus.VALID]);
    } else {
      results.push([word, SpellCheck.WordStatus.INVALID, SUGGESTIONS]);
    }
  }
  callback.call(spellChecker, results);
}
Function to use for word lookup by the spell check handler. This function is
supplied as a constructor parameter for the spell check handler.
@param {!Array<string>} words Unknown words that need to be looked up.
@param {!SpellCheck} spellChecker The spell check handler.
@param {function(!Array)} callback The lookup callback function.