Expected

Deleting all text from the visual view using the backspace key deletes all text and formatting from the HTML view.

Observed

Deleting all text from the visual view using the backspace key leaves empty tags of the inline style(s) applied to the last deleted text.

Reproduced

1. Enter "none bold none italic none strike" into the demonstration app.
2. Select "bold" text.
3. Tap Bold format button.
4. Select "italic" text.
5. Tap Italic format button.
6. Select "strike" text.
7. Tap Strike format button.
8. Place cursor at end of text.
9. Tap Backspace key until text is gone.
10. Tap HTML format button.
11. Notice <b></b> tags remain.

Tested

Google Pixel on Android 7.1.2 with AztecDemo 1.0