Add fenced frames BCD

[chrisdavidmills]

Summary

Fenced frames are part of the set of Privacy Sandbox features being released by default in Chrome 115 and friends. This PR aims to add BCD for all the new features that the fenced frame spec brings.

See my research document for details of all the features added by this PR.

Test results and supporting details

Related issues

[queengooborg]

Based upon results from the mdn-bcd-collector project, it appears that this set of features has landed in Chrome 117. May we update the data accordingly?

[chrisdavidmills]

Based upon results from the mdn-bcd-collector project, it appears that this set of features has landed in Chrome 117. May we update the data accordingly?

@queengooborg done.

[github-actions]

This pull request has merge conflicts that must be resolved before it can be merged.

[Elchi3]

Looking at the IDL, are these features missing in this PR or do they not have an implementation?

• api.Navigator.deprecatedReplaceInURN
• api.HTMLFencedFrameElement.HTMLFencedFrameElement (constructor)

[chrisdavidmills]

• api.Navigator.deprecatedReplaceInURN

• api.HTMLFencedFrameElement.HTMLFencedFrameElement (constructor)

@Elchi3 Hrm, these weren't in the spec when I first started documenting this (it was a while ago). I've had a look in the Chromium source code, and they are there in the IDL.

I've dropped the Chrome eng folk an email to ask when these items were first supported.

[Elchi3]

Marking this as draft, please set as ready once you want me to re-review.

[chrisdavidmills]

Marking this as draft, please set as ready once you want me to re-review.

@Elchi3 OK, I've looked into the missing items some more, and have come to the following conclusions:

• api.Navigator.deprecatedReplaceInURN: This is definitely supported, and was introduced at the same time as the rest of the fenced frames features. I've added this here, and will also add a page to the corresponding content PR.
• api.HTMLFencedFrameElement.HTMLFencedFrameElement (constructor): I don't know where I got that this was included in Chrome from. I later found this IDL, which doesn't include it, and when you try to use it in JS, you get an "Illegal constructor" error. So I am going to leave it out for now.

[Elchi3]

• api.HTMLFencedFrameElement.HTMLFencedFrameElement (constructor): I don't know where I got that this was included in Chrome from. I later found this IDL, which doesn't include it, and when you try to use it in JS, you get an "Illegal constructor" error. So I am going to leave it out for now.

Thanks for looking into this, Chris! I also just now realized that the spec uses an "HTMLConstructor". I will need to read into what this means exactly. See https://html.spec.whatwg.org/multipage/dom.html#html-element-constructors.

[Elchi3]

Thanks Chris. Thanks to OWD's BCD collector project, I can verify the following:
https://mdn-bcd-collector.gooborg.com/tests/api/Fence
https://mdn-bcd-collector.gooborg.com/tests/api/HTMLFencedFrameElement
https://mdn-bcd-collector.gooborg.com/tests/api/Navigator/deprecatedReplaceInURN
https://mdn-bcd-collector.gooborg.com/tests/api/Window/fence

However, in FencedFrameConfig, there are a few properties that seem unsupported for the moment:
https://mdn-bcd-collector.gooborg.com/tests/api/FencedFrameConfig

api.FencedFrameConfig.containerHeight (Window exposure):  No Support
api.FencedFrameConfig.containerWidth (Window exposure):  No Support
api.FencedFrameConfig.contentHeight (Window exposure):  No Support
api.FencedFrameConfig.contentWidth (Window exposure):  No Support

I also don't see them in the IDL:
https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/renderer/core/html/fenced_frame/fenced_frame_config.idl

Can you remove these from this PR or do you have other information?

[chrisdavidmills]

Can you remove these from this PR or do you have other information?

@Elchi3 I suspect this isn't that simple and is to do with the "opaque identifiers" concept around fenced frames (look at the IDL listing, lines 12-15). Saying that, I don't fully understand this, so I will ask the Chrome engineers for some help here.

[Elchi3]

@chrisdavidmills Any news? This PR could land if you remove the 4 properties.

[chrisdavidmills]

@chrisdavidmills Any news? This PR could land if you remove the 4 properties.

I finally managed to talk to someone who can help me track down this information; I should have a definite answer about these properties very soon.

[gtanzer]

It looks like the width and height attributes on the FencedFrameConfig are not currently functional and probably shouldn't be there. They don't need to be documented.

The idea is that at some point we may surface containerWidth, containerHeight, contentWidth, and contentHeight (though they may potentially be opaque), perhaps with different names, but we haven't done it yet.

[chrisdavidmills]

@Elchi3 OK, I've removed those unexposed properties, as per clarification in mdn/content#27781 (comment).

[queengooborg]

Welp...it looks like this is another set of APIs that doesn't seem to be available in BrowserStack. The collector results are reporting these APIs as unsupported.