The latest Chrome build includes in-app payments for Chrome packaged apps in a move that brings Google Wallet integration right to the browser.
Chrome is about to support In app payments for Chrome Packaged Apps thanks to the newly embed Chrome Wallet App also available in the Chrome WebStore at https://chrome.google.com/webstore/detail/google-wallet-service/nmmhkkegccagdldgiimedpiccmgmieda.
If you want to give it a try, make sure to run Google Chrome Canary and install the Chrome Sample App plainly named "In App Payments" at https://github.com/GoogleChrome/chrome-app-samples/tree/master/in-app-payments.
At Google I/O earlier this month, Google announced a new way to send money via Gmail using Google Wallet, as the company continues its "one wallet' approach, which also involves the phasing out of Google Checkout. Google Checkout for Merchants will be retired in six months as Google Wallet takes over. More discussion about that from Google here.