For hybrid mobile apps that have to integrate the Google + Sign In procedure, you may consider using this Cordova plugin
that exposes this piece of functionality. Keep in mind that it appears
that this requires a Google + account for the end user. You can import the plugin in your project following the instructions from here
in the Friends hybrid sample of Telerik Platform.
Also, make sure that you are familiar with the guidelines exposed in this official Google guide
Let me know if you have questions.