Intent to Prototype: Storage Buckets API

[Ayu Ishii]

Contact emails
ay...@chromium.org, pwn...@chromium.org 

Explainer
https://github.com/WICG/storage-buckets/blob/gh-pages/explainer.md

TAG review
https://github.com/w3ctag/design-reviews/issues/562 

Summary
Storage Buckets allows sites the ability to create multiple storage buckets, partitioning data and allowing user agents to delete each bucket independently of other buckets. Each bucket can store data associated with established storage APIs such as IndexedDB and CacheStorage.

Motivation
Currently, when there is storage pressure, sites have no control over how their data gets evicted during browser storage eviction. Today, browsers only have a binary choice to “persist” or “delete” all the data stored by a site.The Storage Buckets API will allow sites to partition data, manage quota and set eviction prioritization so sites can specify what data gets removed first during browser storage eviction.

Risks
Interoperability and Compatibility
If no other browsers end up implementing this API, websites will only be able to use the default bucket that is supported today.

Gecko: Positive (https://github.com/whatwg/storage/issues/2)
WebKit: No signal (https://lists.webkit.org/pipermail/webkit-dev/2020-August/031373.html)
Web developers: Positive - Internal Google partners 

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?
No, but we intend to get full test coverage as we build out the feature.

Link to entry on the Chrome Platform Status
https://chromestatus.com/feature/5739224579964928