Hangs on a certain webpage if "remove unused fonts" is checked.

Describe the bug Loading deferred image and frame content still proceeds as expected, but the extension stops before reaching Step 1. I've only seen this happen on a specific webpage, but there may be others (?).

To Reproduce

1. Visit the webpage.
2. Attempt to save the page as HTML while removing unused fonts.
3. Wait.
4. Step 1 of processing never starts.

Expected behavior All steps complete and the page saves.

Environment

• OS: Android 16
• Browser: IronFox
• Version: 152.0.6