Hi Raj,
Thank you for reaching out to us.
I'm afraid that you will need to use both the extras parameter, as well as the SharedPreferences setting, in order to enable restricted data processing for the AdMob SDK. I would also recommend sticking to the documentation (of using this.getPreferences), since the AdMob SDK checks for SharedPreferences files on relevant activities only (that is, the ones that actually request the ads).
Regards,
Ziv Yves Sanchez
Mobile Ads SDK Team