chrome.commands keyboard shortcuts not working

As you can see in the source code here: https://code.google.com/p/chromium/codesearch#chromium/src/chrome/browser/extensions/api/commands/command_service.cc&l=303&sq=package:chromium&rcl=1409677023

The key binding update is only run when OnExtensionWillBeInstalled callback is triggered.

So you need to uninstall and reinstall your local extension to see the default keyboard command appear in : chrome://extensions/configureCommands

On Chrome 29 you have to navigate to chrome://extensions/ and scroll down to the bottom of the page. On the right side there is a button Keyboard shortcuts.

Modal dialog pops up with all extensions that have registered some commands in their manifest file. But the shortcuts itself are Not set so the user must set them manually.