Have PDFs in a PouchDB database? You can view them using this web app by setting the db, docId, and file parameters in the viewer.html's URL.
For example...
http://.../viewer.html?db=testfiles&docId=helloworld&file=helloworld.pdf
Warning: This only seems to be working in Firefox at the moment.
Based on the PDF Viewer in the PDF.js project as well as this gist.