Web-Facing Change PSA: View Transitions: making callback non-nullable

[Vladimir Levin]

Contact emails

vmp...@chromium.org

Specification

https://drafts.csswg.org/css-view-transitions-1/#additions-to-document-api

Summary

The `startViewTransition` call currently takes an optional nullable callback type with a default value of null: `startViewTransition(optional UpdateCallback? callback = null)` This feature changes this to be a non-nullable type: `startViewTransition(optional UpdateCallback callback)` More details: https://github.com/w3c/csswg-drafts/issues/9460

Blink component

Blink>ViewTransitions>SPA

TAG review

None

TAG review status

Not applicable - this is a minor, but visible, change to the API contract

Risks

Interoperability and Compatibility

If there are cases of startViewTransition that explicitly pass `null` then these will stop working. We don't believe there is any significant number of these, based on the currently low usage of the view transition API, and null being a small subset of those.

Gecko: No signal

WebKit: No signal

Web developers: No signals

Other signals:

WebView application risks

Does this intent deprecate or change behavior of existing APIs, such that it has potentially high risk for Android WebView-based applications?

None

Debuggability

Same as ViewTransitiosn

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

Yes

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

Yes

Flag name on chrome://flags

None

Finch feature name

None

Non-finch justification

None

Requires code in //chrome?

False

Estimated milestones

Shipping on desktop

120

Shipping on Android

120

Shipping on WebView

120

Anticipated spec changes

Open questions about a feature may be a source of future web compat or interop issues. Please list open issues (e.g. links to known github issues in the project for the feature specification) whose resolution may introduce web compat/interop risk (e.g., changing to naming or structure of the API in a non-backward-compatible way).

None

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5194510942601216

This intent message was generated by Chrome Platform Status.