Add a means of navigating PDF content.

[duhrer]

In testing with Science Direct, I noticed that the built-in PDF viewer in Chrome does not inject our scripts or otherwise allow us to control the page.

For more content to test, I tried some MIDI controller PDF manuals, same issue, i.e. it's a browser feature and not anything either site is doing.

I'll have to read up to see if this is exposed somehow, my suspicion is we'd have to detect that they're trying to view a PDF and offer the option to view it in our own modal.

[duhrer]

This stack overflow thread mentions a few approaches and links to other approaches.