Staff member
Quoted from an online source, this blog post. Please take caution when reading up on the linked blog.
As to the commercial antivirus solutions that Google uses, there are a few different brands. For example, in addition to its own technology for protecting against malicious links, Google also uses Microsoft’s Windows Defender antivirus scanner to protect users from phishing attacks. Furthermore, Google’s Chrome Cleanup Tool, which notifies Google Chrome users when it finds potentially unwanted programs (PUPs) or malicious software, is powered by ESET’s malware detection engine.
I have nothing to verify whether if that statement is true or not.