Ready for Trial: BFCache NotRestoredReasons API

[Yuzu Saijo]

Contact emails

yu...@google.com, yu...@chromium.org, fer...@chromium.org

Explainer

https://github.com/rubberyuzu/bfcache-not-retored-reason/blob/main/NotRestoredReason.md

Design docs

https://github.com/rubberyuzu/bfcache-not-retored-reason/blob/main/NotRestoredReason.md#security-and-privacy

Summary

NotRestoredReason API will report the list of reasons why a page is not served from BFcache in a frame tree structure, via PerformanceNavigationTiming API (and Reporting API in the future).

Blink component

UI>Browser>Navigation>BFCache

TAG review

TAG review status

Pending

Risks

Interoperability and Compatibility

Gecko: No signal

WebKit: No signal

Web developers: Positive (https://github.com/w3c/navigation-timing/issues/171#issuecomment-1062672989)

Other signals:

Security

We do not report detailed information about cross-origin iframes. For cross-origin iframes, we only report if they blocked bfcache or not, and we do not report the reasons why.

Goals for experimentation

Ongoing technical constraints

Debuggability

In DevTools console, try: performance.getEntriesByType('navigation')[0].notRestoredReasons;

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

DevTrial instructions

https://github.com/rubberyuzu/bfcache-not-retored-reason/blob/main/HowToTest.md

Flag name

--enable-features=BackForwardCacheSendNotRestoredReasons

Requires code in //chrome?

False

Tracking bug

https://bugs.chromium.org/p/chromium/issues/detail?id=1326344

Launch bug

https://bugs.chromium.org/p/chromium/issues/detail?id=1326343

Estimated milestones

DevTrial on desktop

108

DevTrial on Android

108

Link to entry on the Chrome Platform Status

https://chromestatus.com/feature/5684908759449600

Links to previous Intent discussions

Intent to prototype: https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAP-nMoGAzjUjzv3WmxcRpUSBgnA-AHQ05kh9gXc%2BQB8pRM6%2BfA%40mail.gmail.com