hide x btn when there's no content in DTextInput

Change-Id: If5850c86006f1ad7b64b6da0d8f67f79872ffc20
tower: https://tower.im/projects/d4e0ff64158645f28d99a9ca72d0c27b/todos/13b733fc01504ed6a278c367b161e70e?proto=https
Merge "hide x btn when there's no content in DTextInput"