loading URL whose CSP forbids framing fails in <webview> about positron HOT 2 OPEN

Perhaps we just need to check nsDocShell::GetIsMozBrowserOrApp before deciding whether or not to enforce the frame-ancestor policy, although it returns false in this case, as mFrameType is FRAME_TYPE_REGULAR for the docshell, which seems wrong. So perhaps it's being set incorrectly somewhere.

See my comment, seems like a more general problem than just CSP.

It could also be an issue that nsCSPContext::PermitsAncestry generates ancestorsArray by walking the docshell tree until it reaches a docshell whose document URI scheme is chrome, which won't be the case here, as the URL of the document that contains the mozbrowser will be a file: URL like file:///path/to/positron/test/hello-world/index.html.

I agree checking for the chrome scheme seems suspicious. I would think this code actually wants to check for typeChrome on the parent tree item instead. That's how most code paths seem to find the the top of the content tree.

from positron.

Upstream bug with fix using @jryans suggestions of checking ItemType https://bugzilla.mozilla.org/show_bug.cgi?id=1277102

from positron.