title: Obtain OAuth2 token using android AccountManager?
body: <p>Is it possible to obtain a <code>OAuth2</code> token to use with Google APIs, using the android <code>AccountManager</code>?  The only other way I know of would be to have a <code>webView</code> and make the user log in to obtain the <code>OAuth2</code> token, but it would seem to be a lot of work for that many people would want to do, so if I could just obtain it using <code>AccountManager</code> that would be much better. Is there any functionality like this?</p>