Set "presentation" role for page canvases (issue 14437)
Set "presentation" role for page canvases (issue 14437)

nawawi/pdf.js,showpad/mozilla-pdf.js,timvandermeij/pdf.js,Snuffleupagus/pdf.js,Snuffleupagus/pdf.js,timvandermeij/pdf.js,showpad/mozilla-pdf.js,Shoobx/pdf.js,showpad/mozilla-pdf.js,mozilla/pdf.js,timvandermeij/pdf.js,mozilla/pdf.js,Snuffleupagus/pdf.js,nawawi/pdf.js,nawawi/pdf.js,mozilla/pdf.js,Shoobx/pdf.js,Shoobx/pdf.js