Implement 1p Ephemeral Storage Functionality (functionality)

It would be useful to be able to have Brave visit a site where 1p-storage was ephemeral, in the same way 3p storage is currently by default.

The functionality described here is not intended to cover the settings and options Brave would expose to users (that might or might not change), only to describe the needed underlying capabilities. How 1p ephemeral storage capabilities could be exposed to users, or deployed to benefit users, is covered in other issues (e.g., https://github.com/brave/brave-browser/issues/15097, https://github.com/brave/brave-browser/issues/15018, etc)

This would include the following necessary functionality:

• “1p ephemeral storage sessions” are at site granularity
• DOM storage and cookies in a “1p ephemeral storage session” would be cleared as soon as there have been no top level documents open for the site, for more than <keep alive> seconds
• Other NetworkIsolationKey partitioned storage (HTTP cache, service workers, network cache, etc) would be similarly partitioned

Nice to have:

• “1p ephemeral storage sessions” are isolated from the site’s normal storage area. This means that I should be able to have example.org open in a tab using a standard shields configuration, then open a new example.org tab in “1p ephemeral storage” mode, and that storage set in the “1p ephemeral storage” session would be independent of the standard example.org tab
• Similarly, you could have two different, independent “1p ephemeral storage sessions” at the same time, with the same site, both of which would be independent of standard 1p storage
• “1p ephemeral storage session” tabs taint each other, using sessionStorage logic. So if I open a example.org in a “1p ephemeral storage session”, and then i open another top level document in the same site from that document, both tabs see the same “1p ephemeral storage area”. (This might seem obvious, but I imagine it gets tricky when you could have 2 or more separate “1p ephemeral storage sessions” with the same site.)

[stephendonner]

@goodov: I’ve tried to find the Android corollary, here, but so far am not finding it. I’m not seeing a place where we can add the exception, noted in step 3, above, “added [*.]yandex.com to Always clear cookies when windows are closed, in brave://settings/cookies” We have “Close tabs on exit,” but that’s for browser-session behavior, as is Clear data on exit.

Huh, you’re right. This option is not available on Android, but it’s just a UI limitation, under the hood it should work. I guess we have to add this setting then.

1. Filed https://github.com/brave/brave-browser/issues/19476 to address this (which might/probably depends on another issue).
2. Removed OS/Android as this isn’t yet implemented.

[goodov]

@goodov: I’ve tried to find the Android corollary, here, but so far am not finding it.

I’m not seeing a place where we can add the exception, noted in step 3, above, “added [*.]yandex.com to Always clear cookies when windows are closed, in brave://settings/cookies”

We have “Close tabs on exit,” but that’s for browser-session behavior, as is Clear data on exit.

Huh, you’re right. This option is not available on Android, but it’s just a UI limitation, under the hood it should work. I guess we have to add this setting then.