Gmail is the only product you listed that Google started itself.
Google Maps was built on the acquisitions of Where 2 Technologies, Keyhole and ZipDash.
Chrome is based on WebKit, built at Apple.
Waymo's hardware came from the acquisition of 510 Systems, and the software came from the acquihiring of the team that developed Stanford's self-driving cars for the 2005 and 2007 DARPA challenges, who brought their code with them.
Google Maps was built on the acquisitions of Where 2 Technologies, Keyhole and ZipDash.
Chrome is based on WebKit, built at Apple.
Waymo's hardware came from the acquisition of 510 Systems, and the software came from the acquihiring of the team that developed Stanford's self-driving cars for the 2005 and 2007 DARPA challenges, who brought their code with them.