UserAgent: Mozilla/5.0 (X11; CrOS x86_64 10176.76.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/64.0.3282.190 Safari/537.36
Platform: Platform>Apps>TextApp

Steps to reproduce the problem:
1. Open the ChromeOS Text app
2. Type anything in the Text app window
3. Click the X quit button to close the app; the Text app closes without prompting to save the file.
5. If you re-open the Text app, the content you typed is gone
6. If you go through the same flow but type "Ctrl + W" to close the Text app window instead of clicking the X quit button, the app prompts to save the file

What is the expected behavior?
When clicking the X quit button, the Text app should prompt to save changes like it does when you type "Ctrl + W" to close the Text app window.

What went wrong?
Content typed into the Text app is lost if the user clicks the X quit button before saving the file.

Did this work before? N/A 

Chrome version: 64.0.3282.190  Channel: stable
OS Version: 10176.76.0
Flash Version: