Here are a couple of approaches that might work for you.
Approach 1: Download the PDF file onto your Chromebook using the "Download" button that is on the "Home" tab of the toolstrip. Once it is saved locally on the Chromebook you can print it from there.
Approach 2: Click on the PDF file in the MATLAB Online Current Folder browser and press the Enter key, or right click on the PDF file in the Current Folder browser and select "Open". Either of those actions should cause the PDF file to open up in a new tab in your browser, and you should be able to print it from there.
Approach 3: (I haven't tried this one...) If you have Linux support enabled on Chromebook, you might be able to set up the Linux version of the MATLAB Drive Connector on your Chromebook, which would give you access to the files in your MATLAB Drive folder. You probably also need to make sure that you 1) share the local (Linux) MATLAB Drive folder with Chrome OS, and 2) that you start the MATLAB Drive Connector so the files will sync.
I hope that helps.
