I had the same problem and just hacked together a quick chrome extension to do it. There are a variety of paid-for extensions but I found them bloated and (obviously) not free. Mine is free and I never intend to charge for it 🙂
You don't need to give it access to your Hubspot, LinkedIn or Google Accounts either.
You just need to create a Hubspot form with the first name, last name, title and company name and then paste the form-id and your portal ID into the options page of the chrome extension.
(It ain't pretty, but it's simple and works; TIP: you need to wait a couple of seconds for the linkedin profile to refresh once you've pressed the button before the contact will get created in Hubspot)