title: IOS Google Sign in "No sign-in handlers installed" error
body: <p>I am using the Google Sign-In SDK 2.1.0 for IOS.</p>
  
  <p>in my login ViewController I just simply add the google signin button to my view</p>
  
  <pre><code>    GIDSignIn.sharedInstance().uiDelegate = self
      self.googleLoginBtn = GIDSignInButton(frame: CGRectMake(0, 0, 200, 60))
      self.view.addSubview(self.googleLoginBtn)
  </code></pre>
  
  <p>and I got 2 testing device, in one of the device which has the Youtube App installed, when the login btn is clicked, in open the Youtube app and log me in and go back to my app. Which works perfect.</p>
  
  <p>in another device with some old apps installed, it shows this error</p>
  
  <pre><code>&lt;GIDSignIn: 0x167b97b0&gt; error: Error Domain=com.google.GIDSignIn Code=-3 "No sign-in handlers installed" UserInfo=0x17fe0bf0 {NSLocalizedDescription=No sign-in handlers installed}
  </code></pre>
  
  <p>so...what should be the common practice for handling this??</p>
  
  <p>override it and show a webview for the user to login?</p>
  
  <p>or prompt them for no Google Sign-in handler app??</p>
  
  <p>thanks.</p>
  
  <p>//Update
  I found that in the simulator in works, even no other app is installed, it will present a viewController for login.</p>
  
  <p>but seems they didnt call in my app for both iphone (I did set a break point to verify this)</p>
  
  <pre><code>// Present a view that prompts the user to sign in with Google
  func signIn(signIn: GIDSignIn!,
      presentViewController viewController: UIViewController!) {
    self.presentViewController(viewController, animated: true, completion: nil)
  }
  
  // Dismiss the "Sign in with Google" view
  func signIn(signIn: GIDSignIn!,
      dismissViewController viewController: UIViewController!) {
    self.dismissViewControllerAnimated(true, completion: nil)
  }
  </code></pre>