Looks good to me, but is there any reason this PR can't land now? On Wed, Sep 30, 2026 at 5:35 PM Alex Russell <[email protected]> wrote:
> LGTM1; this is an awesome addition. Thanks for making it happen. > > On TAG review, can you please send an FYI? > > Best, > > Alex > > On Wednesday, September 30, 2026 at 2:47:22 PM UTC+1 Yoav Weiss wrote: > >> *Contact emails* >> [email protected] >> >> *Explainer* >> https://github.com/w3c/long-animation-frames/pull/30#issue-3828859369 >> >> *Specification* >> https://github.com/w3c/long-animation-frames/pull/30 >> >> *Summary* >> Add `styleDuration` and `forcedStyleDuration` information to the Long >> Animation Frame API, enabling developers to distinguish style and layout >> times. >> >> *Blink component* >> Blink>PerformanceAPIs >> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3EPerformanceAPIs%22> >> >> *Web Feature ID* >> Missing feature - >> https://github.com/web-platform-dx/web-features/issues/4453 >> >> *Motivation* >> Currently performance-conscious developers have no way to distinguish >> their style time from their layout time, making CSS performance issues less >> actionable than they can be. This feature enables developers to make that >> distinction. >> >> *Initial public proposal* >> https://github.com/w3c/long-animation-frames/pull/30 >> >> *TAG review* >> I didn't file for a TAG review as these are a few new attributes that >> break up the timings provided by an existing attribute, mimicking its >> existing shape. I don't expect the TAG to have strong opinions on the shape >> of the attributes. >> >> *TAG review status* >> Not applicable >> >> *Origin Trial Name* >> Long Animation Frames - separate style and layout durations >> >> *Goals for experimentation* >> See that the new attributes provide useful data to developers as they >> debug their CSS performance issues. >> >> *Chromium Trial Name* >> LongAnimationFrameStyleDuration >> >> *Link to origin trial feedback summary* >> >> https://groups.google.com/a/chromium.org/g/blink-dev/c/qvGqBcSOFTQ/m/rU6rqKuMCAAJ >> >> *Origin Trial documentation link* >> https://github.com/w3c/long-animation-frames/pull/30#issue-3828859369 >> >> *WebFeature UseCounter name* >> kLongAnimationFrameTimingStyleDuration >> >> *Risks* >> >> >> *Interoperability and Compatibility* >> *As these are new attributes, I don't expect them to have any compat >> impact. As far as interop goes, I'd expect that when other engines adopt >> LoAF, they'd also adopt these attributes.* >> >> *Gecko*: No signal >> Positive on the broader LoAF: >> https://github.com/mozilla/standards-positions/issues/929 >> I'm asking if I should file a more specific issue for these extra >> attributes. >> >> *WebKit*: No signal ( >> https://github.com/WebKit/standards-positions/issues/283) >> No signal for the broader LoAF feature. Unlikely they'd have a strong >> position on these attributes. >> >> *Web developers*: Positive ( >> https://groups.google.com/a/chromium.org/g/blink-dev/c/qvGqBcSOFTQ/m/5DCTOu9KCgAJ >> ) >> >> *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? >> *No information provided* >> >> >> *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 >> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md>?* >> Yes >> >> - https://wpt.fyi/results/long-animation-frame/loaf-style-duration.html: >> styleDuration (9 subtests) >> - https://wpt.fyi/results/long-animation-frame/loaf-layout-duration.html: >> layoutDuration (7 subtests) >> - >> https://wpt.fyi/results/long-animation-frame/loaf-forced-style-duration.html: >> forcedStyleDuration (4 subtests) >> - >> https://wpt.fyi/results/long-animation-frame/loaf-forced-layout-duration.html: >> forcedLayoutDuration, including checking that forced style plus forced >> layout >> adds up to forcedStyleAndLayoutDuration (5 subtests) >> - >> https://wpt.fyi/results/long-animation-frame/loaf-container-queries.html: >> all four attributes when container queries mix style and layout work (6 >> subtests) >> - https://wpt.fyi/results/long-animation-frame/loaf-toJSON.html: now >> also checks styleDuration and layoutDuration in toJSON() >> >> *Flag name on about://flags* >> *No information provided* >> >> *Finch feature name* >> LongAnimationFrameStyleDuration >> >> *Rollout plan* >> Will ship enabled for all users >> >> *Requires code in //chrome?* >> False >> >> *Tracking bug* >> https://issues.chromium.org/issues/476826067 >> >> *Estimated milestones* >> Shipping on desktop 157 >> Origin trial desktop first 148 >> Origin trial desktop last 153 >> Shipping on Android 157 >> Shipping on WebView 157 >> >> *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). >> >> *No changes expected.* >> >> *Link to entry on the Chrome Platform Status* >> https://chromestatus.com/feature/5171478175809536?gate=6516503656660992 >> >> *Links to previous Intent discussions* >> Intent to Prototype: >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOmohSJxRuMp6Ha5RVCjzNfsG0Sj96Y%3Dgy9LnxtM%2Brq-S6DEew%40mail.gmail.com >> Intent to Experiment: >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOmohSJ2PJ0dZxYH48PALOSUenSSV7VuZ9CzTHnGd8u_jTKkcg%40mail.gmail.com >> >> >> This intent message was generated by Chrome Platform Status >> <https://chromestatus.com/>. >> > -- > You received this message because you are subscribed to the Google Groups > "blink-dev" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion visit > https://groups.google.com/a/chromium.org/d/msgid/blink-dev/9403784c-3fb5-47a6-b288-d6c4c26945bdn%40chromium.org > <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/9403784c-3fb5-47a6-b288-d6c4c26945bdn%40chromium.org?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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