getText_() {
    if (this.isBeingEdited_) {
      return super.getText_();
    }
    return this.valueToNote(this.getValue()) || null;
  }
Get the text to be displayed on the field node.
@returns {?string} The HTML value if we're editing, otherwise null.
Null means the super class will handle it, likely a string cast of value.
@protected