We currently have a single WebAuthnManager instance per process, that's shared between all the CredentialContainers. That way the nsPIDOMWindowInner parent has to be tracked by the transaction, as multiple containers could kick off requests simultaneously. I suggest cleaning this up, so that we have one WebAuthnManager instance per each CredentialsContainer and thus each nsPIDOMWindowInner. Just like U2F has one instance per parent window too. This simplifies the communication diagram (at least in my head) a little bit, as each U2F/WebAuthnManager instance also has their own TransactionChild for IPC protocol communication. The manager and child are destroyed when the parent window is.

We have to be careful here to not reintroduce bug 1403818.

Comment on attachment 8933246 [details] Bug 1421616 - Have one WebAuthnManager instance per CredentialsContainer r?jcj J.C. Jones [:jcj] has approved the revision. https://phabricator.services.mozilla.com/D305#7847

Pushed by ttaubert@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/bb739695f566 Have one WebAuthnManager instance per CredentialsContainer r=jcj

Backout by ttaubert@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/f54b084de4f9 Backed out changeset bb739695f566

Pushed by ttaubert@mozilla.com: https://hg.mozilla.org/integration/mozilla-inbound/rev/752801d6a020 Have one WebAuthnManager instance per CredentialsContainer r=jcj