1749825 - Make it possible for scrollable elements in chrome:// documents to opt-in to autodir and honourroot behaviour

Status: RESOLVED FIXED

(Core :: Layout: Scrolling and Overflow, enhancement)

Description

[Mike Conley (:mconley) (:⚙️)]

The Firefox Desktop team plans to work on some UI where we want horizontally-scrollable regions to be scrollable with the mousewheel. I spoke to botond about this, and he mentioned that it might be possible to make the behaviour enabled by "mousewheel.autodir.enabled" and "mousewheel.autodir.honourroot" something that chrome:// documents can opt scrollable regions into.

This bug is for that work.

Comment 1

[Mike Conley (:mconley) (:⚙️)]

Attachment: Bug 1749825 - Make it possible for privileged script to opt elements into mousewheel autodir/honour root behaviour. r?botond!

Comment 2

[Mike Conley (:mconley) (:⚙️)]

Hey botond,

We discussed this before the holiday break, and this is my naive stab at it. It's a WIP with some TODOs for inline documentation, but I wanted to get a sense of whether or not this general approach would work for you, or if you'd prefer something else?

Comment 3

[Botond Ballo [:botond]]

Yep, the approach in this patch looks good to me!

One addition that I believe will be needed for it to work is to propagate the new ScrollMetadata properties around here. (This propagation is from the copy that's sent over IPC from content to the APZ, to the copy retained locally by APZ. We don't copy the whole struct over because some of its properties like the scroll offset require special logic.)

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/56e97c009ff9
Make it possible for privileged script to opt elements into mousewheel autodir/honour root behaviour. r=botond

Comment 5

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/56e97c009ff9