José Dapena Paz (Gerrit)

unread,

Jul 29, 2026, 6:22:35 AM (3 days ago) Jul 29

to chromium...@chromium.org, Chromium Metrics Reviews, asvitkine...@chromium.org, kinuko...@chromium.org, blink-re...@chromium.org, blink-rev...@chromium.org, jmedle...@chromium.org, blink-re...@chromium.org, blink-...@chromium.org, blink-revie...@chromium.org, blink-revi...@chromium.org, blink-rev...@chromium.org, zol...@webkit.org

José Dapena Paz has uploaded the change for review

Commit message

Container Timing: rename containertiming-ignore to containertimingignore

The standard discussion [1] concluded that a dashed HTML content
attribute is inappropriate for the ignore marker. It should be spelled
`containertimingignore` (no dash), consistent with how HTML content
attributes are conventionally named. The JS accessor remains
`containerTimingIgnore`.

[1] https://github.com/WICG/container-timing/issues/65

With this change, `containertimingignore` is now the functional
attribute as. The legacy dashed `containertiming-ignore` spelling is
kept registered without effects: it only fires a new
kContainerTimingIgnoreDashedAttribute use counter so remaining usage
can be tracked and the attribute removed once it drains to zero.

Bug: 539984792

Change-Id: I2af8a3a007c5387a1dce58d23e60cd6fca2564ac

Change diff

Change information

Files:

M third_party/blink/public/mojom/use_counter/metrics/web_feature.mojom
M third_party/blink/renderer/core/display_lock/display_lock_context_test.cc
M third_party/blink/renderer/core/dom/element.cc
M third_party/blink/renderer/core/dom/element.idl
M third_party/blink/renderer/core/html/html_attribute_names.json5
M third_party/blink/renderer/core/html/html_element.cc
M third_party/blink/renderer/core/html/html_element.h
M third_party/blink/renderer/core/html/html_element_container_timing_test.cc
M third_party/blink/renderer/core/layout/layout_object.h
M third_party/blink/renderer/core/paint/pre_paint_tree_walk.cc
M third_party/blink/renderer/core/paint/timing/container_timing.cc
M third_party/blink/renderer/core/paint/timing/container_timing_paint_attribution_tracker.cc
M third_party/blink/renderer/core/paint/timing/container_timing_paint_attribution_tracker_test.cc
M third_party/blink/renderer/core/paint/timing/container_timing_test.cc
M third_party/blink/web_tests/container-timing/use-counter.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/containertiming-and-ignore-on-img-itself.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/containertiming-and-ignore-on-text-itself.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/containertiming-with-child-ignore-and-child-img.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/containertiming-with-ignore-and-child-img.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/ignore-with-containertiming-and-child-img.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/nested-containertiming-and-ignore-on-img.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/nested-containertiming-and-ignore-on-text.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/nested-containertiming-child-img-with-ignore.html
M third_party/blink/web_tests/external/wpt/container-timing/tentative/nested-containertiming-with-ignore.html
M tools/metrics/histograms/metadata/blink/enums.xml

Change size: M

Delta: 25 files changed, 146 insertions(+), 92 deletions(-)

Open in Gerrit

Related details

Attention set is empty

Submit Requirements:

Code-Coverage
Code-Owners
Code-Review
Review-Enforcement

Inspect html for hidden footers to help with email filtering. To unsubscribe visit settings.

Gerrit

satisfied_requirement

unsatisfied_requirement

open

diffy

Philip Rogers (Gerrit)

unread,

Jul 29, 2026, 4:35:24 PM (2 days ago) Jul 29

to José Dapena Paz, Michal Mocny, Scott Haseley, Chris Harrelson, Ethan Jimenez, Dominic Farolino, Chromium LUCI CQ, Chromium Metrics Reviews, chromium...@chromium.org, asvitkine...@chromium.org, blink-re...@chromium.org, blink-re...@chromium.org, blink-rev...@chromium.org, blink-revi...@chromium.org, blink-rev...@chromium.org, blink-revie...@chromium.org, blink-...@chromium.org, jmedle...@chromium.org, kinuko...@chromium.org, zol...@webkit.org

Attention needed from Chris Harrelson, Dominic Farolino, Ethan Jimenez, José Dapena Paz, Michal Mocny and Scott Haseley

Philip Rogers added 1 comment

Patchset-level comments

File-level comment, Patchset 1 (Latest):

Philip Rogers . resolved

Hi José, can you please list what files each reviewer needs to review? Or, maybe we could start with just one primary reviewer and then add the others for enums.xml/web_feature.mojom stamps?

Open in Gerrit

Related details

Attention is currently required from:

Chris Harrelson
Dominic Farolino
Ethan Jimenez
José Dapena Paz
Michal Mocny
Scott Haseley

Submit Requirements:

Code-Coverage
Code-Owners
Code-Review
Review-Enforcement

Inspect html for hidden footers to help with email filtering. To unsubscribe visit settings.

Gerrit

satisfied_requirement

unsatisfied_requirement

open

diffy

José Dapena Paz (Gerrit)

unread,

Jul 30, 2026, 2:12:23 PM (2 days ago) Jul 30

to Michal Mocny, Scott Haseley, Chromium LUCI CQ, Chromium Metrics Reviews, chromium...@chromium.org, asvitkine...@chromium.org, blink-re...@chromium.org, blink-re...@chromium.org, blink-rev...@chromium.org, blink-revi...@chromium.org, blink-rev...@chromium.org, blink-revie...@chromium.org, blink-...@chromium.org, jmedle...@chromium.org, kinuko...@chromium.org, zol...@webkit.org

Attention needed from Michal Mocny and Scott Haseley

José Dapena Paz added 1 comment

Patchset-level comments

File-level comment, Patchset 1 (Latest):

Philip Rogers . resolved

Hi José, can you please list what files each reviewer needs to review? Or, maybe we could start with just one primary reviewer and then add the others for enums.xml/web_feature.mojom stamps?

José Dapena Paz

Sorry, I realized Scott Hasseley can review all. I got a bit confused. I will withdraw most of the review requests.

Open in Gerrit

Related details

Attention is currently required from:

Michal Mocny
Scott Haseley

Submit Requirements:

Code-Coverage
Code-Owners
Code-Review
Review-Enforcement

Inspect html for hidden footers to help with email filtering. To unsubscribe visit settings.

Gerrit

satisfied_requirement

unsatisfied_requirement

open

diffy

Scott Haseley (Gerrit)

unread,

Jul 30, 2026, 4:31:53 PM (2 days ago) Jul 30

to José Dapena Paz, Michal Mocny, Chromium LUCI CQ, Chromium Metrics Reviews, chromium...@chromium.org, asvitkine...@chromium.org, blink-re...@chromium.org, blink-re...@chromium.org, blink-rev...@chromium.org, blink-revi...@chromium.org, blink-rev...@chromium.org, blink-revie...@chromium.org, blink-...@chromium.org, jmedle...@chromium.org, kinuko...@chromium.org, zol...@webkit.org

Attention needed from José Dapena Paz and Michal Mocny

Scott Haseley added 2 comments

Commit Message

Line 18, Patchset 1 (Latest):attribute as. The legacy dashed `containertiming-ignore` spelling is

Scott Haseley . unresolved

Did this get cut off (may "as" isn't needed)?

Line 19, Patchset 1 (Latest):kept registered without effects: it only fires a new


kContainerTimingIgnoreDashedAttribute use counter so remaining usage
can be tracked and the attribute removed once it drains to zero.

Scott Haseley . unresolved

A couple thoughts/questions:

I'm not sure there's an advantage to keeping the old attribute around only for the UseCounter since removing it would be functionally equivalent (I think). That is, using "containertiming-ignore" on a site should have no effect if you remove the attribute (i.e. it shouldn't cause an error).

That said, this is a breaking change, so this won't this affect Origin Trial users? It won't cause errors, but the behavior will change. I think there are a few strategies:

 1. Wait until after the OT ends and remove it (without UseCounter). That's typically a good time to make breaking changes.

 2. Map containertiming-ignore to containertiming so they both work, and then remove containertiming-ignore once the OT ends. This is safer than removing now, but it adds more complexity to the code that is maybe necessary.

 3. Make the change now (M153), but inform OT participants about the change so they can update their sites. They would probably need to have both attributes for a while to support old versions of Chrome (otherwise they'll need to potentially filter out results from older versions).

Is there a UseCounter for this attribute? That might help decide.

Open in Gerrit

Related details

Attention is currently required from:

José Dapena Paz
Michal Mocny

Submit Requirements:

Code-Coverage
Code-Owners
Code-Review

No-Unresolved-Comments

Review-Enforcement

Inspect html for hidden footers to help with email filtering. To unsubscribe visit settings.

Gerrit

satisfied_requirement

unsatisfied_requirement

open

diffy

José Dapena Paz (Gerrit)

unread,

Jul 31, 2026, 1:26:01 PM (13 hours ago) Jul 31

to Michal Mocny, Scott Haseley, Chromium LUCI CQ, Chromium Metrics Reviews, chromium...@chromium.org, asvitkine...@chromium.org, blink-re...@chromium.org, blink-re...@chromium.org, blink-rev...@chromium.org, blink-revi...@chromium.org, blink-rev...@chromium.org, blink-revie...@chromium.org, blink-...@chromium.org, jmedle...@chromium.org, kinuko...@chromium.org, zol...@webkit.org

Attention needed from Michal Mocny and Scott Haseley

José Dapena Paz added 2 comments

Commit Message

Line 18, Patchset 1:attribute as. The legacy dashed `containertiming-ignore` spelling is

Scott Haseley . resolved

Did this get cut off (may "as" isn't needed)?

José Dapena Paz

I rewrote the sentence 2-3 times then still was lucky enough to introduce this spelling! The new paragraph is way different now and does not include the same sentence.

Line 19, Patchset 1:kept registered without effects: it only fires a new


kContainerTimingIgnoreDashedAttribute use counter so remaining usage
can be tracked and the attribute removed once it drains to zero.

Scott Haseley . resolved

A couple thoughts/questions:
I'm not sure there's an advantage to keeping the old attribute around only for the UseCounter since removing it would be functionally equivalent (I think). That is, using "containertiming-ignore" on a site should have no effect if you remove the attribute (i.e. it shouldn't cause an error).
That said, this is a breaking change, so this won't this affect Origin Trial users? It won't cause errors, but the behavior will change. I think there are a few strategies:
 1. Wait until after the OT ends and remove it (without UseCounter). That's typically a good time to make breaking changes.
 2. Map containertiming-ignore to containertiming so they both work, and then remove containertiming-ignore once the OT ends. This is safer than removing now, but it adds more complexity to the code that is maybe necessary.
 3. Make the change now (M153), but inform OT participants about the change so they can update their sites. They would probably need to have both attributes for a while to support old versions of Chrome (otherwise they'll need to potentially filter out results from older versions).
Is there a UseCounter for this attribute? That might help decide.

José Dapena Paz

I finally opted for (2):

Only a single use counter shared for them.
Console warning when using the old spelling. I don't try to deduplicate the warning as that would imply adding a boolean in the window, or using the deprecation infrastructure (that has a lot of commit overhead). Reason is: nobody detected yet using it.

Once the trial is finished, we just drop the legacy spelling.

Open in Gerrit

Related details

Attention is currently required from:

Michal Mocny
Scott Haseley

Submit Requirements:

Code-Coverage
Code-Owners
Code-Review

Review-Enforcement

Inspect html for hidden footers to help with email filtering. To unsubscribe visit settings.

Gerrit

satisfied_requirement

unsatisfied_requirement

open

diffy

Scott Haseley (Gerrit)

unread,

Jul 31, 2026, 7:18:38 PM (7 hours ago) Jul 31

to José Dapena Paz, Michal Mocny, Chromium LUCI CQ, Chromium Metrics Reviews, chromium...@chromium.org, asvitkine...@chromium.org, blink-re...@chromium.org, blink-re...@chromium.org, blink-rev...@chromium.org, blink-revi...@chromium.org, blink-rev...@chromium.org, blink-revie...@chromium.org, blink-...@chromium.org, jmedle...@chromium.org, kinuko...@chromium.org, zol...@webkit.org

Attention needed from José Dapena Paz and Michal Mocny

Scott Haseley voted and added 4 comments

Votes added by Scott Haseley

Code-Review

+1

4 comments

Patchset-level comments

File-level comment, Patchset 3 (Latest):

Scott Haseley . resolved

LGTM

Commit Message

Line 18, Patchset 1:attribute as. The legacy dashed `containertiming-ignore` spelling is

Scott Haseley . resolved

Did this get cut off (may "as" isn't needed)?

José Dapena Paz

I rewrote the sentence 2-3 times then still was lucky enough to introduce this spelling! The new paragraph is way different now and does not include the same sentence.

Scott Haseley

Happens to me all the time 😊.

Line 19, Patchset 1:

kept registered without effects: it only fires a new
kContainerTimingIgnoreDashedAttribute use counter so remaining usage
can be tracked and the attribute removed once it drains to zero.

Scott Haseley . resolved

A couple thoughts/questions:
I'm not sure there's an advantage to keeping the old attribute around only for the UseCounter since removing it would be functionally equivalent (I think). That is, using "containertiming-ignore" on a site should have no effect if you remove the attribute (i.e. it shouldn't cause an error).
That said, this is a breaking change, so this won't this affect Origin Trial users? It won't cause errors, but the behavior will change. I think there are a few strategies:
 1. Wait until after the OT ends and remove it (without UseCounter). That's typically a good time to make breaking changes.
 2. Map containertiming-ignore to containertiming so they both work, and then remove containertiming-ignore once the OT ends. This is safer than removing now, but it adds more complexity to the code that is maybe necessary.
 3. Make the change now (M153), but inform OT participants about the change so they can update their sites. They would probably need to have both attributes for a while to support old versions of Chrome (otherwise they'll need to potentially filter out results from older versions).
Is there a UseCounter for this attribute? That might help decide.

José Dapena Paz

I finally opted for (2):
Only a single use counter shared for them.
Console warning when using the old spelling. I don't try to deduplicate the warning as that would imply adding a boolean in the window, or using the deprecation infrastructure (that has a lot of commit overhead). Reason is: nobody detected yet using it.
Once the trial is finished, we just drop the legacy spelling.

Scott Haseley

SGTM. It's not as gross as I thought it might be, and it's nice to get the implementation and tests up-to-date with the resolution.

File third_party/blink/renderer/core/html/html_element.cc

Line 4453, Patchset 3 (Latest): // measured usage of the attribute is negligible, so per-page dedup state is

Scott Haseley . unresolved

typo: I think "deduped"?

Open in Gerrit

Related details

Attention is currently required from:

José Dapena Paz
Michal Mocny

Submit Requirements:

Code-Coverage
Code-Owners
Code-Review
No-Unresolved-Comments
Review-Enforcement

Inspect html for hidden footers to help with email filtering. To unsubscribe visit settings.

Gerrit

satisfied_requirement

unsatisfied_requirement

open

diffy

Reply all

Reply to author

Forward

Container Timing: rename containertiming-ignore to containertimingignore [chromium/src : main]

José Dapena Paz (Gerrit)

José Dapena Paz has uploaded the change for review

Commit message

Change diff

Change information

Related details

Philip Rogers (Gerrit)

Philip Rogers added 1 comment

Related details

José Dapena Paz (Gerrit)

José Dapena Paz added 1 comment

Related details

Scott Haseley (Gerrit)

Scott Haseley added 2 comments

Related details

José Dapena Paz (Gerrit)

José Dapena Paz added 2 comments

Related details

Scott Haseley (Gerrit)

Scott Haseley voted and added 4 comments

Votes added by Scott Haseley

4 comments

Related details