Facebook cookie tracking is dead code, and broken since Electron 44

[micahflee]

Split out of #719, which fixed the same underlying problem for X. Filing rather than fixing, because the right answer for Facebook is probably deletion, not a port.

The underlying finding

Chromium stopped exposing the Cookie request header to webRequest listeners. BaseAccountController registers ses.webRequest.onSendHeaders(...), and handleCookieTracking reads details.requestHeaders["Cookie"] out of it, so that map no longer fills.

Verified with the same listener on both runtimes:

Electron	Chromium	requestHeaders["Cookie"]
41.10.7	146	ct0=PROBEVALUE
44.4.3	152	null

For X this broke login outright: getCookie returned null, graphqlGetViewerUser logged ct0 is null, and the account was left with no username.

Why Facebook is different

Nothing reads Facebook's cookies. FacebookAccountController declares a cookies field and writes to it in handleCookieTracking, but there is no getCookie method, no IPC handler, and no preload binding — getCookie is exposed only as X:getCookie. The map has been write-only since it was added.

So there is no user-visible breakage to fix. What is there is dead code that also stopped working, plus a trap: anyone who later adds a Facebook cookie reader against this map gets silent nulls, which is a slow thing to debug.

Options

1. Delete it. Remove the cookies field and the handleCookieTracking override. The base class already has a no-op default (added in Upgrade dependencies: 79 advisories down to 24, no criticals #719), so nothing else has to change. If that leaves X and Facebook both opted out, the onSendHeaders registration in BaseAccountController can go too.
2. Give Facebook a working getCookie on the model X now uses — session.cookies.get({ url, name }) — but only if there is a near-term need for it. X needs cookies for GraphQL deletes; it is not clear Facebook has an equivalent.

Option 1 unless someone knows of planned work that needs Facebook cookies.

Pointers

• X fix: commit 609b78a1 on deps-upgrade-2026-09, plus src/account_x/__tests__/unit/controller.cookies.unit.test.ts for the shape of a test that does not presuppose the header.
• The mock in src/__tests__/platform-fixtures/electronMocks.ts supplies a Cookie header to onSendHeaders, so the suite cannot currently catch this class of failure. It now also has a seedable cookie jar.
• Facebook code: src/account_facebook/facebook_account_controller.ts, the cookies field and handleCookieTracking.

(This was written by an LLM.)