[desktop] File upload dialog can't see user's files

[Michael Terry]

On the desktop, when a web site asks for a file dialog to pick a file (like uploading a file), the dialog that appears is useless. I can't see any files in my home directory. It just appears blank.

This is on xenial's 0.23+16.04.20151103-0ubuntu1 version of webbrowser-app.

Examples:
https://www.cs.tut.fi/~jkorpela/forms/file.html (there is a file upload button a little ways down)
Gmail, when uploading an attachment

[Michael Terry (mterry)]

(I assume this is bundled up in desktop not having the same file exchange infrastructure as Touch does, as bug 1491279 also shows.)

[Olivier Tilloy (osomon)]

Not seeing that on wily desktop, but I think I know what’s going on: on xenial webbrowser-app is running confined by apparmor, and by default access to the file system is denied. We should probably deny that conditionally (it makes sense when using the content hub transfer capabilities, but it doesn’t on desktop with a traditional filepicker approach).

[Olivier Tilloy (osomon)]

jdstrand suggests using content-hub on desktop too, he says they have a file picker now

[Michael Terry (mterry)]

Tested this again on current xenial desktop. Looks like we do use content-hub now. But as might have been expected, there's very few apps registered on a typical desktop install. I just see the Browser itself and Contacts (which doesn't work).

[Olivier Tilloy (osomon)]

Yes, we basically shifted the problem from webbrowser-app to content-hub and the availability of content sources on desktop.
That said, as this seems to be the general direction we are aiming at, I’ll mark this bug fixed for webbrowser-app, and we can add tasks for content-hub and/or other apps that should act as content sources.