Google Cloud DNS doesn't provide any DNS-based blocking / filtering like SafeDNS, OpenDNS or similar solutions.
Have a look at the documentation Google Cloud DNS:
Google Cloud DNS is a scalable, reliable, and managed authoritative
Domain Name System (DNS) service running on the same infrastructure as
Google. It has low latency, high availability and is a cost-effective
way to make your applications and services available to your users.
Cloud DNS translates requests for domain names like www.google.com
into IP addresses like 74.125.29.101. Cloud DNS is programmable. You
can easily publish and manage millions of DNS zones and records using
our simple user interface, command-line interface or API.