Comment # 1 on bug 1056923 from Bernhard Wiedemann

Also, key and signature are correct:
wget http://dl.google.com/linux/chrome/rpm/stable/x86_64/repodata\
/repomd.xml{,.asc}
gpg -d repomd.xml.asc 
gpg: assuming signed data in 'repomd.xml'
gpg: Signature made 2017-08-30T17:36:13 UTC
gpg:                using RSA key 1397BC53640DB551
gpg: Good signature from "Google Inc. (Linux Packages Signing Authority)
<linux-packages-keymaster@google.com>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: EB4C 1BFD 4F04 2F6D DDCC  EC91 7721 F63B D38B 4796
     Subkey fingerprint: 3B06 8FB4 789A BE4A EFA3  BB49 1397 BC53 640D B551