Code review comment for lp:~ahayzen/webbrowser-app/fix-1491279-depend-on-download-manager

webbrowser_app.tests.test_downloads.TestDownloads.test_picker reliably fails on my desktop, most likely because there’s no app installed that can handle the application/pdf mimetype.
Ideally this should be mocked in contenthub so that the test can always be run with predictable results. If not possible, please make it conditional (or remove it altogether, are we guaranteed to have a pdf reader application always installed on touch devices?).