According to this post it was in the beta, but it's not in the release?
console.log is only available after you have opened the Developer Tools (F12 to toggle it open and closed). Funny thing is that after you've opened it, you can close it, then still post to it via console.log calls, and those will be seen when you reopen it. I'm thinking that is a bug of sorts, and may be fixed, but we shall see.
I'll probably just use something like this:
function trace(s) {
if ('console' in self && 'log' in console) console.log(s)
// the line below you might want to comment out, so it dies silent
// but nice for seeing when the console is available or not.
else alert(s)
}
and even simpler:
function trace(s) {
try { console.log(s) } catch (e) { alert(s) }
}