Comment 0 for bug 1751634

Steps to reproduce:
1. Install Ubuntu 16.04 LTS
2. Install test application as Notepadqq - `snap install notepadqq`
3. Try to launch it as root

$ which notepadqq
/snap/bin/notepadqq

$ sudo snap run notepadqq
mkdir: cannot create directory '/run/user/0': Permission denied
No protocol specified
QXcbConnection: Could not connect to display :0.0
Aborted (core dumped)

$ pkexec snap run notepadqq
mkdir: cannot create directory '/run/user/0': Permission denied
QXcbConnection: Could not connect to display
Aborted (core dumped)

$ sudo notepadqq
mkdir: cannot create directory '/run/user/0': Permission denied
No protocol specified
QXcbConnection: Could not connect to display :0.0
Aborted (core dumped)
$ gksudo notepadqq
No protocol specified
QXcbConnection: Could not connect to display :0.0

Expected results:
user is able to run snap-installed program as root

Expected results:
user is unable to run snap-installed program as root

Note:
first seen on AskUbuntu ( https://askubuntu.com/q/1009698/66509 ).

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: snapd 2.29.4.2 [modified: usr/share/dbus-1/services/io.snapcraft.Launcher.service]
ProcVersionSignature: Ubuntu 4.4.0-116.140-generic 4.4.98
Uname: Linux 4.4.0-116-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
CurrentDesktop: MATE
Date: Sun Feb 25 22:10:49 2018
InstallationDate: Installed on 2018-01-04 (52 days ago)
InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
SourcePackage: snapd
UpgradeStatus: No upgrade log present (probably fresh install)