Private Aggregation API: Increase contribution limit to 100 for Protected Audience callers

Chrome 131
Stable release date: November 12th, 2024

Unless otherwise noted, the following changes apply to Chrome 131 stable channel release for Android, ChromeOS, Linux, macOS, and Windows.

CSS
CSS Anchor Positioning: anchor-scope
The anchor-scope property allows limiting the visibility of anchor names to a given subtree.
Tracking bug #40281992 | ChromeStatus.com entry | Spec

CSS font-variant-emoji
The font-variant-emoji CSS property provides a way to control between colored (emoji-style) and monochromatic (text-style) emoji glyphs. This can be also done by adding an emoji variation selector, specifically U+FE0E for text and U+FE0F for emoji, after each emoji codepoint.
MDN font-variant-emoji | ChromeStatus.com entry

CSS highlight inheritance
With CSS highlight inheritance, the CSS highlight pseudo-classes, such as ::selection and ::highlight, inherit their properties through the pseudo highlight chain, rather than the element chain. The result is a more intuitive model for inheritance of properties in highlights.
Inheritance changes for CSS selection styling | ChromeStatus.com entry | Spec

Improvements to styling structure of <details> and <summary> elements
Support more CSS styling for the structure of <details> and <summary> elements to allow these elements to be used in more cases where disclosure widgets or accordion widgets are built on the web. In particular, this change removes restrictions that prevented setting the display property on these elements, and adds a ::details-content pseudo-element to style the container for the part that expands and collapses.
Tracking bug #1469418 | ChromeStatus.com entry | Spec

@page margin boxes
Add support for page margin boxes, when printing a web document, or exporting it as PDF.
The @page margin boxes let you define the contents in the margin area of a page, for example to provide custom headers and footers, rather than using the built-in headers and footers generated by the browser.
A margin box is defined using an at-rule inside a CSS @page rule. The appearance and the contents of a margin box are specified with CSS properties inside the at-rule, including the content property. Counters are also supported, for page numbering. The specification defines two special counter names: page for the current page number and pages for the total number of pages.
Add content to the margins of web pages when printed using CSS | Tracking bug #320370 | ChromeStatus.com entry | Spec

@property support <string> syntax
Support for <string> syntax component name for registered custom properties.
Tracking bug #357751736 | ChromeStatus.com entry | Spec

Select parser relaxation
This makes the HTML parser allow tags in <select> in addition to <option>, </option><optgroup>, and ---
This change is in support of the customizable <select> feature.
Tracking bug #335456114 | ChromeStatus.com entry

Support currentcolor in relative color syntax
Allow relative colors in CSS (using the from keyword) to use currentcolor as a base. This lets you set complementary colors, based on an element's text color, for that element's borders, shadows, or backgrounds.
This feature also includes use cases where color functions are nested with a dependency on currentcolor, for example color-mix(in srgb, rgb(from currentcolor r g b), white)) or rgb(from rgb(from currentcolor 1 g b) b g r).
Tracking bug #325309578 | ChromeStatus.com entry | Spec

Support external SVG resources for clip-path, fill, stroke, and marker-* properties
This feature adds support for external references for clip paths, markers, and paint servers (for the fill and stroke properties). For example, clip-path: url("resources.svg#myPath").
Tracking bug #40134477 | ChromeStatus.com entry | Spec

Web APIs
Direct Sockets API
Allows Isolated Web Apps to establish direct transmission control protocol (TCP) and user datagram protocol (UDP) communications with network devices and systems as well as listen to and accept incoming connections.
Tracking bug #909927 | ChromeStatus.com entry | Spec

Exempt Speculation-Rules Header from CSP restrictions
updates the integration between speculation rules and CSP so that CSP only applies to <script type="speculationrules">, and not to the Speculation-Rules header.</script>

FedCM as a trust signal for the Storage Access API
Reconciles the FedCM and Storage Access APIs by making a prior FedCM grant a valid reason to automatically approve a storage access request.

noopener-allow-popups COOP value
Some origins can contain different applications with different levels of security requirements. In those cases, it can be beneficial to prevent scripts running in one application from being able to open and script pages of another same-origin application.
In such cases, it can be beneficial for a document to ensure its opener cannot script it, even if the opener document is a same-origin one.
The noopener-allow-popups Cross-Origin-Opener-Policy value lets documents define that.

WebHID on dedicated workers
Enables WebHID inside dedicated worker contexts. This lets you perform heavy I/O and processing of data from a HID device on a separate thread, helping to reduce the performance impact on the main thread.

WebRTC RTCRtpEncodingParameters.scaleResolutionDownTo
An API that configures WebRTC encoders to scale input frames if they are greater than the specified maxWidth and maxHeight. This API is similar to scaleResolutionDownBy except that resolution constraints are expressed in absolute terms (for example, 640x360) as opposed to relative terms (for example, scale down by 2), avoiding race conditions related to changing input frame size on the fly.

WebXr hand input module Level 1
Exposes hand joint data on XrInputSources for use during a WebXr session. This allows developers to have more fine grained interactions during WebXr sessions.

Rendering and graphics
WebGPU clip distances
Adds the optional GPU feature clip-distances that allows setting user-defined clip distances in vertex shader outputs. This technique is particularly useful for the applications that need to clip all vertices in a scene that are beyond a user-defined plane, such as many CAD applications.

WebGPU: GPUCanvasContext getConfiguration()
Once GPUCanvasContext configure() has been called with a configuration dictionary, you can use the GPUCanvasContext getConfiguration() method to check the canvas context configuration. It includes GPU device, format, usage, viewFormats, colorSpace, toneMapping, and alphaMode members. As discussed in issue 4828, web apps can use it to detect whether HDR canvas is supported in WebGPU.

Privacy
Attribution-Reporting API: Remove aggregation key identifier size limit for trigger registrations
Previously the aggregation key identifier length limit was checked in both source and trigger registrations. As this limit is not for privacy and it's not persisted in the storage, it's being removed in trigger registrations.
ChromeStatus.com entry

Private Aggregation API: Increase contribution limit to 100 for Protected Audience callers
Enables Protected Audience script runners to make up to 100 contributions per Private Aggregation report, compared to the current limit of 20.

Private Aggregation limits the number of histogram contributions that can be embedded in a single aggregatable report, dropping any additional contributions. Shared Storage callers can work around the limit by invoking another Shared Storage operation. However, Protected Audience callers have no persistent storage, so they lose their excess contributions at the end of their auction. Note that this change is privacy neutral as the API's contributions are still limited by the same privacy budget.

Due to padding, each Protected Audience report will have a larger payload, even if it did not need the larger contribution limit. We expect that these larger reports will increase the cost of operating the Aggregation Service.
Tracking bug #360160864 | ChromeStatus.com entry

Origin trials
Playout Statistics API for WebAudio
The AudioContext.playoutStats API allows an application to measure the quality and latency of audio playout using WebAudio.
Origin Trial | ChromeStatus.com entry | Spec

ServiceWorkerStaticRouterTimingInfo
Adds timing information for ServiceWorker Static routing API, exposed in navigation timing API and resource timing API for developer use.

Service Worker provides timing information to mark certain points in time. We add two Static routing API-relevant timing information: RouterEvaluationStart, time to start matching a request with registered router rules, and CacheLookupStart, time to start looking up the cache storage if the source is "cache". In addition, we also add two router source information, the matched router source and the final router source.
Origin Trial | ChromeStatus.com entry

Summarization API
A JavaScript API for producing summaries of input text, backed by an AI language model.
Origin Trial | Summarization API documentation | Tracking bug #351744634 | ChromeStatus.com entry

Translator API
A JavaScript API to provide language translation capabilities to web pages.
Origin Trial | Translator API documentation | Tracking bug #322229993 | ChromeStatus.com entry

Deprecations and removals
Remove the CSS Anchor Positioning property inset-area
With the CSS Working Group resolution on renaming the inset-area property to position-area, this removal cleans up the implementation in Chromium for a standards compliant feature.
Tracking bug #352360007 | ChromeStatus.com entry

Remove the ability to disable BeforeunloadEventCancelByPreventDefault
Feature BeforeunloadEventCancelByPreventDefault was shipped in Chrome 117, but there is an enterprise policy that allows this flag to be force-disabled. The enterprise policy will be removed in Chrome 131.
ChromeStatus.com entry

Remove non-standard GPUAdapter requestAdapterInfo() method
The WebGPU Working Group decided it was impractical for requestAdapterInfo() to trigger a permission prompt so they've removed that option and replaced it with the GPUAdapter info attribute so that web developers can get the same GPUAdapterInfo value synchronously.
ChromeStatus.com entry | Spec