Intent to Experiment: Reverse origin trial for Standardized CSS zoom

[Stefan Zager]

Contact emails

sza...@chromium.org

Explainer

None

Specification

https://github.com/w3c/csswg-drafts/pull/9699

Design docs

https://docs.google.com/document/d/1AcnDShjT-kEuRaMchZPm5uaIgNZ4OiYtM4JI9qiV8Po/edit

Summary

Create a reverse origin trial to allow sites to opt out of the "Standardized CSS Zoom" feature. Existing sites may rely on chromium's legacy non-spec-compliant behavior of the CSS zoom property. This origin trial will allow individual sites to opt out of the new spec-compliant behavior, to allow them time to migrate to the newly-specified behavior.

Blink component

Blink>Paint

TAG review

None

TAG review status

Pending

Risks

Interoperability and Compatibility

This is meant to mitigate the compatibility risks of the Standardized CSS Zoom feature. The origin trial will have a limited duration, so sites that participate in the origin trial but are not updated to support the new behavior will still break when the origin trial ends.

WebView application risks

See Interoperability and Compatibility risks

Goals for experimentation

To provide a reprieve for sites that are broken by the new zoom behavior.

Ongoing technical constraints

None

Debuggability

None

Will this feature be supported on all six Blink platforms (Windows, Mac, Linux, ChromeOS, Android, and Android WebView)?

Yes

Is this feature fully tested by web-platform-tests?

The legacy chromium-specific behavior is tested by chromium-internal tests, but not WPT.

Flag name on chrome://flags

StandardizedBrowserZoom

Finch feature name

StandardizedBrowserZoom

Requires code in //chrome?

False

Estimated milestones

M128

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5198254868529152

Links to previous Intent discussions

https://groups.google.com/a/chromium.org/g/blink-dev/c/W8j6RKDeRoM/m/FyCKOAG9AAAJ

This intent message was generated by Chrome Platform Status.

[Mike Taylor]

Thanks for creating this - can you clarify how long you would like this deprecation trial to last?

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[Stefan Zager]

On Tue, Jun 25, 2024 at 7:24 AM Mike Taylor <mike...@chromium.org> wrote:

Thanks for creating this - can you clarify how long you would like this deprecation trial to last?

That will depend on the response from site owners and the level of uptake, but the initial period will be one year.

[Mike Taylor]

On 6/25/24 4:23 PM, Stefan Zager wrote:

On Tue, Jun 25, 2024 at 7:24 AM Mike Taylor <mike...@chromium.org> wrote:

Thanks for creating this - can you clarify how long you would like this deprecation trial to last?

That will depend on the response from site owners and the level of uptake, but the initial period will be one year.

Typically it is feature teams that determine the length of a deprecation trial, rather than site owners - based on webcompat analysis, which may include outreach to known affected sites. Per https://www.chromium.org/blink/launching-features/#deprecation-trial - deprecation trials normally only last 6 milestones, and are renewed in 6 milestone increments. However, exceptions are possible with 3 LGTMs.

If you think 1 year is the correct length for the ecosystem, can you please provide justification for an exception here?

[Stefan Zager]

On Tue, Jun 25, 2024 at 1:54 PM Mike Taylor <mike...@chromium.org> wrote:

On 6/25/24 4:23 PM, Stefan Zager wrote:

On Tue, Jun 25, 2024 at 7:24 AM Mike Taylor <mike...@chromium.org> wrote:

Thanks for creating this - can you clarify how long you would like this deprecation trial to last?

That will depend on the response from site owners and the level of uptake, but the initial period will be one year.

Typically it is feature teams that determine the length of a deprecation trial, rather than site owners - based on webcompat analysis, which may include outreach to known affected sites. Per https://www.chromium.org/blink/launching-features/#deprecation-trial - deprecation trials normally only last 6 milestones, and are renewed in 6 milestone increments. However, exceptions are possible with 3 LGTMs.

If you think 1 year is the correct length for the ecosystem, can you please provide justification for an exception here?

I mistakenly thought that one year was the standard period for a deprecation trial; in light of that documentation, I think six months is appropriate.

[Mike Taylor]

On 6/25/24 5:31 PM, Stefan Zager wrote:

On Tue, Jun 25, 2024 at 1:54 PM Mike Taylor <mike...@chromium.org> wrote:

On 6/25/24 4:23 PM, Stefan Zager wrote:

On Tue, Jun 25, 2024 at 7:24 AM Mike Taylor <mike...@chromium.org> wrote:

Thanks for creating this - can you clarify how long you would like this deprecation trial to last?

That will depend on the response from site owners and the level of uptake, but the initial period will be one year.

Typically it is feature teams that determine the length of a deprecation trial, rather than site owners - based on webcompat analysis, which may include outreach to known affected sites. Per https://www.chromium.org/blink/launching-features/#deprecation-trial - deprecation trials normally only last 6 milestones, and are renewed in 6 milestone increments. However, exceptions are possible with 3 LGTMs.

If you think 1 year is the correct length for the ecosystem, can you please provide justification for an exception here?

I mistakenly thought that one year was the standard period for a deprecation trial; in light of that documentation, I think six months is appropriate.

No worries - we can revisit in 6 months if needed.

LGTM

[Mike Taylor]

Oh - also, can you request the Privacy, Security, Debuggability bits in chromestatus? thx

[Stefan Zager]

On Wed, Jun 26, 2024 at 8:06 AM Mike Taylor <mike...@chromium.org> wrote:

Oh - also, can you request the Privacy, Security, Debuggability bits in chromestatus? thx

Done.