Add support for PDFs.

[Daniel Steinberg]

Highlighting is only currently supported on web pages. It would be nice if PDFs loaded in the browser could also be highlighted.

[Varun]

I was looking for a tool that does this(highlighting text in PDFs) when I came across the extension. I haven't looked into the source code of the extension but I'm interested in working on PDF highlighting.

[Horacio Mijail Antón Quiles]

I'd love love love love this. I'd sponsor the feature.