[MBlume]

"Know your data is safe

Your data is secured through encryption when we connect you to open Wi-Fi hotspots. It's like your data has a private tunnel to drive through."

So that's a yes

ETA: Of course this does mean Google has the plaintext, but then, your ISP always has the plaintext unless you're bringing your own encryption, so this is really no different.

[athenot]

Google is also in a much better position to make use of that data & metadata than the typical ISP.

[Dylan16807]

At the same time they're not going to invite shoddy monitoring/injection services like many ISPs have done.