Intent to Ship: Resource Timing: Add spec-compliant Service Worker Router timing fields

[Keita Suzuki]

Contact emails

suzuk...@chromium.org, sisid...@chromium.org, yyana...@chromium.org

Specification

https://github.com/w3c/resource-timing/pull/415

Summary

Adds the `workerMatchedRouterSource` and `workerFinalRouterSource` attributes to the Resource Timing and Navigation Timing APIs. These attributes allow developers to identify which Service Worker Static Router rule was matched and the final source used for the request. Note on Deprecation: This change focuses exclusively on adding the spec-compliant fields. We will be sending a separate Intent to Deprecate (I2D) for the existing non-compliant fields (`workerMatchedSourceType` and `workerFinalSourceType`) once we have gathered sufficient usage data from our UseCounters.

Blink component

Blink>ServiceWorker

Web Feature ID

resource-timing

Motivation

The original field names (`workerMatchedSourceType` and `workerFinalSourceType`) were introduced during the experimental phase and used throughout the Origin Trial (M131–M139) . However, the specification has since settled on the names `workerMatchedRouterSource` and `workerFinalRouterSource` to be more descriptive and consistent with the broader API. Renaming these fields is critical for ensuring that Chromium remains spec-compliant and provides a stable, interoperable interface for web developers.

Initial public proposal

No information provided

TAG review

No information provided

TAG review status

Issues addressed

Goals for experimentation

None

Risks

Interoperability and Compatibility

No information provided

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. This change is purely additive (adding the new fields) and does not change the behavior of existing APIs in a way that would break WebView-based applications

Debuggability

No information provided

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?

Yes

Flag name on about://flags

No information provided

Finch feature name

No information provided

Non-finch justification

No information provided

Rollout plan

Will ship enabled for all users

Requires code in //chrome?

False

Availability expectation

Feature is available on Web Platform Baseline within 12 months of launch in Chrome.

Adoption expectation

Feature is used by specific partner(s) to provide functionality within 12 months of launch in Chrome. Feedback from the Origin Trial indicated that developers already find the router source information highly valuable for tracking and attribution.

Adoption plan

We will notify developers of the new field names via technical blog posts and documentation updates. The temporary coexistence of old and new fields ensures a smooth transition for current users.

Non-OSS dependencies

Does the feature depend on any code or APIs outside the Chromium open source repository and its open-source dependencies to function?

No.

Estimated milestones

Shipping on desktop	149
Shipping on Android	149
Shipping on WebView	149

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. The corresponding spec changes are already added. These fields are being added specifically to match the finalized specification. Reference: https://github.com/w3c/resource-timing/pull/415

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5172259800088576?gate=5871730453250048

This intent message was generated by Chrome Platform Status.