So I went with parsing the history because there can be multiple outstanding needinfo? requests.  From my testing, the flag call only gave me the most recent needinfo? flag.  I have some debug output in this code that shows when needinfo? flags are added and removed.  Any that are added and not later removed are outstanding needinfo? flags:

> INFO 2013-08-29 13:27:52,689 scrum.models bug 904488 adding needinfo sync-1@bugzilla.tld
> INFO 2013-08-29 13:27:52,689 scrum.models bug 904488 removing needinfo sync-1@bugzilla.tld
> INFO 2013-08-29 13:27:52,689 scrum.models bug 904488 adding needinfo rkaptein@mozilla.com
> INFO 2013-08-29 13:27:52,689 scrum.models bug 904488 adding needinfo chengan.xiong@tcl.com
> INFO 2013-08-29 13:27:52,689 scrum.models bug 904488 removing needinfo rkaptein@mozilla.com
> INFO 2013-08-29 13:27:52,689 scrum.models bug 904488 adding needinfo jcheng@mozilla.com
> INFO 2013-08-29 13:27:52,690 scrum.models bug 904488 adding needinfo mlee@mozilla.com

This shows me that there are outstanding needinfo? requests for chengan.xiong, jcheng, and mlee.  But if I make a call to get the flags I get this:

> $ curl -s https://api-dev.bugzilla.mozilla.org/latest/bug/904488/flag | python -mjson.tool

```json
{
    "flags": [
        {
            "id": "705347",
            "name": "needinfo",
            "requestee": {
                "name": "mlee"
            },
            "setter": {
                "name": "praghunath"
            },
            "status": "?",
            "type_id": "800"
        }
    ]
}
```

As you can see, it only gives me the most recent needinfo? for mlee.  This seems like a bug in the REST API.  I just asked in #bmo to see if they think it is.  But for now, the only way to get all three appears to be the history.

In a later revision, I would like to add the ability to have all of the flags and to turn on/off UI elements associated with specific flags.  But for now, needinfo? is the most important one to the fxos-perf team and we'd like to get this in ASAP.