code: function unescapeReferenceToken(rawReferenceToken) {
      // Unescapes reference token. See Section 3 of specification.
  
      var referenceToken = rawReferenceToken;
      var character;
      var escapeSequence;
      var pair;
      var replaceRegExp;
  
      // Order of unescaping does matter.
      // That's why an array is used here and not hash.
      for (var i = 0; i < SPECIAL_CHARACTERS.length; i++) {
        pair = SPECIAL_CHARACTERS[i];
        character = pair[0];
        escapeSequence = pair[1];
        replaceRegExp = new RegExp(escapeSequence, 'g');
        referenceToken = referenceToken.replace(replaceRegExp, character);
      }
  
      return referenceToken;
    }
docs: Decodes all escape sequences in given |rawReferenceToken|.
  @param {!string} rawReferenceToken
  @returns {string} Unescaped reference token.