title: Using google-signin without metadata tags
body: <p>I am trying to use the google signin lib without the metadata tags. (explanation for this at the end)</p>
  <p>I largely seem to have this working but when my page loads I get an uncaught exception:</p>
  <blockquote>
  <p>Missing required parameter 'client_id'</p>
  </blockquote>
  <p>The auth lib is obviously still trying to initialise despite me not specifying the client id in the metadata.</p>
  <p>Is there any way of turning the lib off so that it does attempt the initialise until I call the <a href="https://developers.google.com/identity/sign-in/web/reference#gapiauth2initwzxhzdk20paramswzxhzdk21" rel="nofollow noreferrer">gapi.auth2.init</a> function?</p>
  <h3>Why I don't want to use metadata tags</h3>
  <p>I have the example from the <a href="https://developers.google.com/identity/sign-in/web/sign-in" rel="nofollow noreferrer">docs</a> working great but I want to incorporate this lib into my angular app that uses an angular service to sign in. I want my angular service to control when the lib is initialised, when it signs in and deal with the results. The example using metadata tags is great but seems to do everything itself without giving me much control.
  For example, I want a loading state as the lib is initialising and logging in, I do not want to show a login button until this initial state has been resolved.</p>