Scroll into view in iframe not working from iframe parent context

[bryanph]

Because of this line:

compute-scroll-into-view/src/index.ts

Line 259 in 9b4e9e6

const scrollingElement = document.scrollingElement || document.documentElement

Here it accesses document as a global, but when you execute this function from the iframe's parent's context, the document outside of the iframe is selected which results in the wrong behavior.

I think instead of getting document as a global here, we can also get it from the element directly.
So that would become something like:

const targetDocument = target.ownerDocument!
const scrollingElement = targetDocument.scrollingElement || targetDocument.documentElement

[stipsan]

PRs welcome! 😄