Direct links: calling chrome.tabs API for the tab URL and Wiley: calling to the active tab DOM for a PDF iframe source

[lmmx]

Wiley doesn't provide any link to the PDF, but a content script could retrieve it from the iframe source embedded on the page

[vsbuffalo]

Thanks @lmmx — I will review and pull this in when I get a chance. I'm still a bit swamped at the moment but it should be soon.