measureIntersection: use root=document

[samouri]

summary

• When iframed we should likely always use root:document for InObs. Otherwise rootBounds=null.
• question: should default for needsRootBounds be true or false?

I recommend viewing the diff without whitespace changes

[samouri]

I'm struggling with the failing unit test here. Unsure what rootBounds is supposed to be equal to for the root=document case.

My impression was document window's viewport. So for the case of an iframe'd element, width should be: iframe.contentWindow.innerWidth.

What I'm actually seeing is: Math.min(iframe.ownerDocument.body.clientWidth, iframe.contentWindow.innerWidth).

[dvoytenko]

I'm struggling with the failing unit test here. Unsure what rootBounds is supposed to be equal to for the root=document case.

My impression was document window's viewport. So for the case of an iframe'd element, width should be: iframe.contentWindow.innerWidth.

What I'm actually seeing is: Math.min(iframe.ownerDocument.body.clientWidth, iframe.contentWindow.innerWidth).

I think the spec probably spells it out. But off the top of my head, documentElement.clientWidth/Height do sound like a reasonable thing here.