CrOS FilesApp: allow install deb by sharing with crostini

Currently deb files can only be installed into the crostini
container in FilesApp if they are already in Linux files.

Now, files will be shared with the container if they are in
a sharable volume such as Downloads or Drive, so deb files
at these locations can be installed.

Bug: 878324
Change-Id: I126568eefec1506a205035d9f8a585548f92b527
Reviewed-by: Timothy Loh <>
Commit-Queue: Joel Hockey <>
Cr-Commit-Position: refs/heads/master@{#603415}
3 files changed