1785305 - [resize-observer] When first observing an element with ResizeObserver, lastReportedSize should get initialized with a -1 x -1 size

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Mozilla Apprentice]

A resolution was made for csswg-drafts/#3664.

[resize-observer] The initial size of ResizeObservation

• RESOLVED: When first observing an element with ResizeObserver, lastReportedSize gets initialized with a -1 x -1 size

Discussion.

Comment 1

[Daniel Holbert [:dholbert]]

dshin: maybe you'd be interested to take this, since you've been in the ResizeObserver neighborhood recently?

Comment 2

[Oriol Brufau [:Oriol]]

This will make this hack unnecessary, so please remove it while doing this: https://searchfox.org/mozilla-central/rev/f3616b887b8627d8ad841bb1a11138ed658206c5/dom/base/ResizeObserver.cpp#298-309

Comment 3

[David Shin[:dshin]]

Attachment: Bug 1785305: Set Resize Observer's last reported size to -1x-1 initially. r=#layout-reviewers

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/14e81415cae1
Set Resize Observer's last reported size to -1x-1 initially. r=emilio

Comment 5

[Andreea Pavel [:apavel]]

https://hg.mozilla.org/mozilla-central/rev/14e81415cae1

Comment 6

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/35745 for changes under testing/web-platform/tests

Comment 7

[Martin Robinson (email:[e-mail])]

Attachment: Bug 1785305: Anonymous children of elements with content-visibility should not be skipped for layout r=emilio

Some anonymous children are important for properly sizing their parents
even when those parents hide content with content-visibility. This is
shown by regressions in the proper layout of some form elements with
content-visibility.

This change introduces a more conservative approach for avoiding layout
of hidden content. Instead of leaving all children dirty during reflow,
reflow anonymous frames (and nsComboboxDisplayFrame, a specialized kind
of anonymous frame). This change means that frames may only lay out some
of their children, so it must introduce some more changes to assumptions
during line layout.

In addition, this change renames content-visibility related methods in
nsIFrame in order to make it more obvious what they do.

Comment 8

[Emilio Cobos Álvarez [:emilio]]

Wrong bug #?

Comment 9

[Martin Robinson (email:[e-mail])]

(In reply to Emilio Cobos Álvarez (:emilio) from comment #8)

Wrong bug #?

Yes. Sorry. I'm not sure what happened there.

Comment 10

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR was closed without merging

Comment 11

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by jgraham