Configuring Identity Provider with Google Authentication (in OCP-22289) allows other google account to authenticate even when the "hostedDomain" field is empty. 

Always

1. Create OAuth client ID on Google APIs (Refer to https://developers.google.com/identity/protocols/oauth2/openid-connect sections "Setting up OAuth 2.0", "Obtain OAuth 2.0 credentials". The redirect URL must be set to be https://oauth-openshift.apps.<cluster-name>.<cluster-domain>/oauth2callback/<idp-provider-name>, idp-provider-name must equal the value of .spec.identityProviders.name in later step)
 
2. oc create secret generic google-secret --from-literal=clientSecret={...} -n openshift-config

3. oc apply -f - <<EOF
apiVersion: config.openshift.io/v1
kind: OAuth
metadata:
  name: cluster
spec:
  identityProviders:
  - name: googleidp
    mappingMethod: lookup
    type: Google
    google:
      clientID: {...}
      clientSecret:
        name: google-secret
      hostedDomain: ~
EOF

4. while trying to login , using google identity provider in the openshift console it allows other google accounts to authenticate.

Trying to login into the openshift console using Google Identity Provider, it allows other google accounts to authenticate.

Trying to login into the openshift console using Google Identity Provider, it should not allow other google accounts to authenticate if the "hostedDomain" field is empty.