This plugin depends on small extensions to supported OAuth authentication point, that still pending for review. To build the plugin against stable-2.10 Gerrit tree, these changes must be cherry-picked: [1],[2] and [3].
As of April 20, 2015 Google shuts down its deprecated OpenID 2.0 provider. To simplify the migration google-oauth-povider plugin seamlessly supports linking of OAuth identity to existing Gerrit accounts. To activate it, add the following configuration option to plugin config section:
[plugin "gerrit-oauth-provider-google-oauth"] client-id = "<id>" client-secret = "<secret>" link-to-existing-openid-accounts = true