Keyboard Shortcuts in Google Chrome / Chromium Extensions

Unfortunately there's no way to hook into global hotkeys. The best you can do is add a window event keypress listener.

Source: a Chromium developer post on the chromium-extensions group.

Just as an update it's actually being developed now:

http://developer.chrome.com/trunk/apps/commands.html

Keyboard shortcuts are implemented with chrome.commands in Chrome 25 and above: developer.chrome.com/apps/commands.html.