Add more options for identifying iframe

[Zhang Zhao]

Hi,
as per documentation, switch.toFrame(id) can be done by id ONLY.. What if a scenario where the iframe doesn’t contain id attribute like the snapshot attached? How do I switch to this iframe? I think it is a pretty common use case. So I wanted to request a feature enrichment for iframe specifically such that there are more options that users can choose to identify iframe component with Sitespeed.io out of box without having selenium involved. Thanks.

[Peter Hedenskog]

I added a PR where you can use xpath or css selecors.

[Zhang Zhao]

Awesome! Thank you.