This extensions allows you to set hotkeys for controlling Google Play Music.
This very lightweight extension adds hotkeys to control basic Google Play Music streaming features. Hotkeys are implemented for Play/Pause (Alt-P), Next Track (Alt-Right) and volume controls (Alt-Up/Down). Keyboard shortcuts can be customised on the chrome://extensions page, through the Keyboard Shortcuts link. Install this extension if you are looking for a simple way to control the Google Play Music streaming player with your keyboard. Update: version 0.2 fixes volume controls.