Deduct file type from content-disposition
Deduct file type from content-disposition

A user encountered a response that looks like:

URL: some gibberish
Headers:

    Content-Type: application/octet-stream
    Content-Disposition: attachment; filename="something.pdf"

In the Chrome extension, the "attachment" content disposition is almost
always ignored (i.e. the PDF Viewer will try to view it anyway). So we
need to fall back to the Content-Disposition header if the URL check is
inconclusive.

caremerge/pdf.js,timvandermeij/pdf.js,yurydelendik/pdf.js,adlerweb/pdf.js-Touch,showpad/mozilla-pdf.js,macroplant/pdf.js,Snuffleupagus/pdf.js,1and1/pdf.js,macroplant/pdf.js,Rob--W/pdf.js,jasonjensen/pdf.js,xavier114fch/pdf.js,WhitesteinTechnologies/wt-vaadin-pdf.js,showpad/mozilla-pdf.js,mysterlune/pdf.js,websirnik/pdf.js,skalnik/pdf.js,ydfzgyj/pdf.js,WhitesteinTechnologies/wt-vaadin-pdf.js,Shoobx/pdf.js,a0preetham/pdf.js,mozilla/pdf.js,mainegreen/pdf.js,xavier114fch/pdf.js,skalnik/pdf.js,Shoobx/pdf.js,nawawi/pdf.js,mainegreen/pdf.js,tinderboxhq/pdf.js,adlerweb/pdf.js-Touch,tinderboxhq/pdf.js,1and1/pdf.js,showpad/mozilla-pdf.js,Rob--W/pdf.js,mukulmishra18/pdf.js,ydfzgyj/pdf.js,timvandermeij/pdf.js,timvandermeij/pdf.js,a0preetham/pdf.js,caremerge/pdf.js,Snuffleupagus/pdf.js,mozilla/pdf.js,Shoobx/pdf.js,mysterlune/pdf.js,mukulmishra18/pdf.js,nawawi/pdf.js,yurydelendik/pdf.js,macroplant/pdf.js,jasonjensen/pdf.js,websirnik/pdf.js,Snuffleupagus/pdf.js,nawawi/pdf.js,mozilla/pdf.js