How to get a unique ClientID/DeviceID from chrome app/extension?
In your manifest.json
{
  ...
  "permissions": [
    "enterprise.deviceAttributes"
  ]
}
Execute the following code when your application loads. It will fetch the value of the device identifier of the directory API, that is generated by the server : enterprise_deviceAttributes It will output 32 characters long alpha numeric id. For example,
352z2721-77cc-aa1d-91a2-rc382c42a5a0
chrome.enterprise.deviceAttributes.getDirectoryDeviceId(function(deviceId) {
    console.debug('DeviceIdOfTheDirectoryAPI', deviceId);
});
 
    