renderReply_(textArea, originalMsg) {
    var replyLineToken = '\n> ';
    var replyBody =
        utils.text.prettyTextWrap(originalMsg, (78 - replyLineToken.length));
    textArea.value = goog.string.format(
        '\n\n%s:\n%s', chrome.i18n.getMessage('promptEncryptSignReplyHeader'),
        replyLineToken + replyBody.split('\n').join(replyLineToken));
    textArea.setSelectionRange(0, 0);
  }
Renders the original message to which the user wants to reply.
@param {HTMLTextAreaElement} textArea The text area where the reply body
    will be displayed.
@param {string} originalMsg The original message.
@private