After months of work, Chrome OS unveils Google Now Cards in its last Dev Update
for those who have enabled the experimental chrome://flags/#enable-google-now
Don't be surprised if you don't see all your Now Cards. Google Now on Chrome shows only a subset of the Now cards you see on your mobile device, which uses your device's location.
In the screenshot below, I only get the Paris weather because that's where I am.
And if you want to turn off Google Now, click on the notification icon in the lower right corner of your screen to open the Notifications Center, click the gear icon and uncheck the box next to "Google Now".