Permissions prompt support in Servo

[Manishearth]

Currently Servo cannot trigger permissions prompts. This is going to be necessary to be able to expose getUserMedia() and some of the XR stuff.

This will likely be somewhere in the embedder API.

Ideally, for getUserMedia() we can have a "pick your device" menu as well (may need a separate API)

cc @paulrouget

[jdm]

There is some overlap with the work for #23057, too.

[paulrouget]

Where is the code that scan for media devices? In Servo or in the embedder?

[Manishearth]

It's currently in Gstreamer. This can be changed to make it an embedder hook.

The primary goal of this issue is to have some ability to throw up a permissions prompt, we can extend that for getUserMedia()'s media selection later. I bring it up now so that whatever we design can be extended with selection dropdowns/etc.

[gatoWololo]

Hello,

I started looking at this issue. I followed jdm's link to #23057, I see how #20428 and #20429 moved use of tinyfiledialogs to the embedder.

I saw components/script/dom/permissions.rs has the functions permission_request(...) and prompt_user(...). Is this not the

Currently Servo cannot trigger permissions prompts

that this issue refers to? If so, what's the difference and where should it go? Thanks.

[jdm]

Manish's statement wasn't completely correct. Servo does partially support the DOM Permissions API, but only displays prompts for bluetooth-related permissions checks and only on Linux. We will need to add DOM Permissions API integration into Servo's GetUserMedia implementation, but first we should create the right infrastructure for that by fixing #23057, which is really the issue that I intended to send you.

[gatoWololo]

Cool, I'll look at #23057 then.

[Manishearth]

We're going to need hooks for permissions prompts in embedder stuff for Hololens, at least cc @paulrouget

Immersive mode is supposed to trigger permissions prompts in many cases.

[paulrouget]

I like the prompt service we have in Gecko: https://dxr.mozilla.org/mozilla-central/source/toolkit/components/windowwatcher/nsIPromptService.idl

Would that work for your use cases (getUserMedia and immersive mode)?

[Manishearth]

Probably yeah. We'd need some kind of embedder API and a native implementation for the hololens.

[paulrouget]

WIP https://github.com/paulrouget/servo/tree/prompt
Still need to figure out how to properly block on the dialogs for the UWP port.