[Bug]: Using viewer html in iframe [srcdoc] makes viewer always cause "Setting up fake worker"

[Luxusio]

Attach (recommended) or Link to PDF file

Not a pdf file related bug

Web browser and its version

Chromium 142.0.7444.162

Operating system and its version

macOS Sequoia 15.6.1

PDF.js version

5.4.149

Is the bug present in the latest PDF.js version?

Not tested

Is a browser extension

No

Steps to reproduce the problem

1. Copy & Paste entire viewer html into iframe
2. Warning message occurs

What is the expected behavior?

Warning message not occurs

What went wrong?

in iframe's srcdoc, windows.location is always about:srcdoc.
then api.js decides it has different origin.

and then, api.js tries to create a URL object, but it fails. Then pdf.js always setup fake worker.js

Link to a viewer

No response

Additional context

No response