How can I add google analytics tracking to a pdf I uploaded to Marketo? I am trying to track page views for the pdf URL.

You cannot...a PDF cannot serve Javascript. 

If you have a link to the PDF on a page, you can fake a pageview based on the click by hardcoding the trackPageview event into the link. See this for inspiration: http://stackoverflow.com/questions/10309726/how-to-use-trackpageview-in-google-analytics