Bug 1069412 - Email constantly asks me to reauthenticate

[jrburke]

• If an SMTP or IMAP connection fails due to a bad oauth token, allow for a forced renewal try of the access_token then try again.
• To prevent aggressive retries, uses a_transientLastRenew timestamp, generated from date.PERFNOW, which uses performance.now when possible, to track if a renew was recently attempted.
• Since performance.now can be reset or changed, we only know we will get a higher value within the lifetime of the window/worker, so js/composite/account.js resets the value on account instantiation. This is the part where I am not sure if this is the desired way to do this for GELAM, so appreciate there could be more idiomatic GELAM ways to do that.
• I moved the credsUpdatedCallback work to be done inside oauth.js, instead of being being done by the callers in the client.js files, since the retry pathways would also need to do it.

[asutherland]

oi! date.NOW()!

[asutherland]

This looks good but it needs new test coverage because things that could potentially infinitely loop scare me. The test should be pretty easy so I'm just going to do write one / modify an existing one now. I'll make the date.NOW change too. May alter the time warp slightly.

[asutherland]

It turns out that the GELAM tests are a bit more work than I was expecting since we didn't actually ever create a full oauth-authed test. I'm still doing the test, but it's going to be a later-Thursday-afternoon thing since creating the fake oauth-server and the infrastructure to use it involves a medium amount of plumbing. I think this is the right call, still, though, especially since (after some more enhancement that only the front-end needs) we'll also be able to use this to integration-test the entire oauth flow in the front-end.