After the field has been rendered sets up the plugin (create the Element for the clear button, attach listeners).
@private
function(textField) {
            this.isTextArea = (this.textField.inputEl.dom.type.toLowerCase() == 'textarea');

            this.createClearButtonEl();
            this.addListeners();

            this.repositionClearButton();
            this.updateClearButtonVisibility();

            this.addEscListener();
        }