1363856 - [meta] Implement WebExtensions API to give access to specific preferences

Status: NEW

(WebExtensions :: General, enhancement, P3)

Description

[Bob Silverberg [:bsilverberg]]

There are a number of preferences to which some popular legacy add-ons need access. These APIs will use browserSetting [1] to manage which extension has control over the pref. If it makes sense, the APIs will be added to the privacy namespace, but often that is not where they will belong, so we need somewhere else to put them.

These will differ from Chrome's contentSettings API [2] in that these prefs control the browser globally - they do not change settings on a site by site basis. Andy suggested the namespace `browserSettings`, which sounds good to me, so I am going to run with that unless anyone has a better idea.

[1] https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/privacy/BrowserSetting
[2] https://developer.chrome.com/extensions/contentSettings

Comment 1

[Bob Silverberg [:bsilverberg]]

Note that most of these are documented in https://docs.google.com/document/d/1HZiI-dqFATzLpmTtN1Bg6tD8y4N0Ne3D74LEWWgttOk/edit#

Comment 2

[quality+bugzilla]

Will this allow WebExtensions to modify most prefs, or will this just have a small list?

In particular, will it allow WebExtensions to modify cookie prefs?

Comment 3

[Bob Silverberg [:bsilverberg]]

(In reply to quality+bugzilla from comment #2)
> Will this allow WebExtensions to modify most prefs, or will this just have a
> small list?

This is only about granting access to a specific set of prefs, so the latter.

> 
> In particular, will it allow WebExtensions to modify cookie prefs?

Bug 1363860 will grant access to control cookie behaviour via a specific pref, but that's all that's planned for cookies at the moment. If there is something else you need, please open a separate bug for it, and feel free to make it block this bug.

Comment 4

[Reşat SABIQ (Reshat)]

Without ability to get and set the following preferences, my Blend In extension loses most of its functionality if i convert it to WebExtension:
appversion.override
oscpu.override
platform.override
buildID.override
useragent.override

It will end up spoofing only HTTP User-Agent header (to say it's Windows, etc.), while all the navigator properties will be saying it's Linux, for instance.

Does this bug cover the above preferences, or should i open a new one?

P.S. I don't see the preferences in
https://developer.mozilla.org/en-US/Add-ons/WebExtensions/API/browserSettings
or elsewhere.

Comment 5

[Andy McKay]

We consider each preference individually, so please file seperate bugs and making them block on this bug.