1618584 - Stop using XUL to implement the HTML marquee element

Status: RESOLVED FIXED

(Toolkit :: General, defect, P2)

Description

[Mats Palmgren (inactive)]

The frame tree for data:text/html,<marquee>x looks like this:

Block(marquee)
  XULScroll(div)
    Box(div)
      Box(div)
        TableWrapper(div)
          Table(div)
            TableRowGroup(div)
              TableRow(div)
                TableCell(div)
                  Block(div)
                    Block(div)
                      Text "x"
...

We should replace the XUL boxes (XULScroll and Box) with CSS boxes.

Alternatively, remove support for <marquee> altogether.

Comment 1

[Mats Palmgren (inactive)]

These XUL boxes comes from: https://searchfox.org/mozilla-central/source/toolkit/content/widgets/marquee.css#6,11
Changing those to a standard block results in the desired HTMLScroll/Block boxes.
However, that appears to break the scrolling behavior so I guess we need some adjustments to marquee.js too.

Comment 2

[Brian Grinstead [:bgrins]]

FWIW the content is set at https://searchfox.org/mozilla-central/rev/b2ccce862ef38d0d150fcac2b597f7f20091a0c7/toolkit/content/widgets/marquee.js#404-430. I was expecting to simplify or change this markup in Bug 1425874 but it turned out to be tangential to the work needed to de-XBL it.

Ideally we'd remove the UA widget entirely and implement entirely in HTMLMarqueeElement using HTML and CSS animations (see https://cs.chromium.org/chromium/src/third_party/blink/renderer/core/html/html_marquee_element.cc?l=61-77&rcl=d7e0211189498697ccc172476680adec021ded0d). But it's probably not worth the effort for this element.

Maybe the problem with the CSS change from Comment 1 won't be too hard to find by debugging marquee.js

Comment 3

[Emilio Cobos Álvarez (:emilio)]

Attachment: Bug 1618584 - Simplify marquee widget to not use XUL. r=bgrins,mats

And also to use more similar markup and setup between
horizontal/vertical marquee.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c3eb53d6395a
Simplify marquee widget to not use XUL. r=bgrins,mats

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/c7acd68206d1
Some tests are asserting less.

Comment 6

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/c3eb53d6395a
https://hg.mozilla.org/mozilla-central/rev/c7acd68206d1