paramsForReuse() {
    return this.paramsForReuse_;
  }
Returns value specified in the carlo.launch(options.paramsForReuse). This is handy
when Carlo is reused across app runs. First Carlo app successfully starts the browser.
Second carlo attempts to start the browser, but browser profile is already in use.
Yet, new window is being opened in the first Carlo app. This new window returns
options.paramsForReuse passed into the second Carlo. This was single app knows what to
do with the additional windows.

@return {*}