1723797 - Add a separate pref to select Fission process isolation strategy when fission.autostart is enabled

Status: RESOLVED FIXED

(Core :: DOM: Content Processes, enhancement, P2)

Description

[Nika Layzell [:nika] (ni? for response)]

Currently, the pref fission.autostart controls a number of distinct features, including both fission-required features like SHIP and the specific process selection strategy of putting every site in a distinct process. For Android, we will want to use a different process isolation strategy, while still enabling the other features enabled by fission.autostart.

This bug tracks adding a new pref to allow controlling the specific process selection strategy when Fission is enabled independently from the fission.autostart pref.

The initial values for this pref should include:

1. No Isolation - Every website is loaded in the shared web content process.
2. Isolate Everything - Every website is given its own webIsolated content process.

We'll probably want to eventually add more settings, like:

3. Isolate COOP - Isolate pages which respond with a Cross-Origin-Opener-Policy header.
4. Isolate High Value - Isolate pages which have met our heuristic for being "high value" (e.g. being logged-in, having certain cookies, etc.)

Comment 1

[Chris Peterson [:cpeterson]]

Agi asked if this new policy pref (and COOP site isolation bug 1723801) could land in Nightly 93 or 94.

Comment 2

[Nika Layzell [:nika] (ni? for response)]

Attachment: Bug 1723797 - Add a separate pref to control process isolation strategy when fission.autostart is enabled, r=farre!,agi!,johannh!

This new pref will be used on android to enable high-value-only process
isolation. An initial version of high-value-only process isolation is
also implemented in this bug, using the permission manager to track
whether a site is high-value due to having served a
Cross-Origin-Opener-Policy header.

Future high-value permissions due to things like logging into a site and
OAuth flows can be tracked in the same way, by adding the permission to
the permissions database.

In the future, it might be valuable to provide UI for visualizing what
sites are considered high-value at any point in time, but this works
fine for now.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/cc8a625549a8
Add a separate pref to control process isolation strategy when fission.autostart is enabled, r=farre,johannh,necko-reviewers,dragana

Comment 4

[Sandor Molnar[:smolnar]]

https://hg.mozilla.org/mozilla-central/rev/cc8a625549a8