Logging out of managed chromebook running in single app kiosk mode - google-chrome-extension

Question

I am a 'Chrome for Business and Education' admin for a fleet of chromebooks which I have configured to run in Single App Kiosk mode. The kiosk app in question is really simple. All I did was take the example code from this page that uses the 'webview tag' (without controls, as we need all the whole screen for the app in question) and change the URL. The app has installed perfectly in all managed devices.
The problem now is that there are times when we want to be able to exit the kiosk app and return to the chromebook login screen. Right now the only way of doing this is to shut the machine down, start it and exit from the kiosk app boot screen by pressing Ctrl+Alt+S. The whole process takes 30 seconds plus per machine (the fleet contains 50). So we really need to be able to just quit out of the kiosk app and go back to the login screen (which would take about 5 seconds or less).
Now, I could just add a quit button to the screen (as per the second example app with navigation controls from the page referenced above) but this means we lose screen space for the app. The preferred solution is to close the app with keystrokes (e.g. Ctrl+Shift+L). But how do you do this in this context? I have tried adding conventional onkeydown javascript to the page containing the webview tag and this seems to be ignored. I have also tried using the 'chrome commands API', and whilst I can see that the shortcut had been registered against the extension (by clicking 'Keyboard shortcuts' on the chrome://extensions tab) it has no effect. The kiosk app window remains stubbornly open.
Does anyone know if this is possible and if so how?
Cheers,
Miles

Answer 1

In your manifest.json file add this entry to create the command for the app.
"commands": {
"exit-app": {
"suggested_key": {
"default": "Ctrl+Shift+L"
},
"description": "Exit the app"
}
}
Then you need to add code to your background script file to listen for the command. This code will close all windows in the app when it receives the exit-app command you created in the manifest.
chrome.commands.onCommand.addListener(function(command) {
switch(command) {
case 'exit-app':
exitApp();
break;
}
});
function exitApp() {
chrome.app.window.getAll().forEach(function(win) {
win.close();
});
}
Note that the key combination is only suggested, and might be ignored if another app or Chrome keyboard shortcut already uses that combination. You do still need to go to the Keyboard shortcuts link on the chrome://extensions page and verify that the key combination has actually been set for your app.