SHELL COMMANDS AT THE BOTTOM OF THIS DESCRIPTION:
Starting from scratch, I quickly demonstrate how to download, install and configure the necessary components to run Ubuntu Gnome 3 Desktop (Flashback) on a Google Cloud Compute instance running the server version of Ubuntu 16.04.2 LTS (Xenial Xerus) and interface with it via VNC Viewer through an encrypted SSH tunnel.

1 - Creating and configuring a Google Cloud Compute instance.
2 - Updating Linux.
3 - Downloading and installing Gnome Desktop, autocutsel (to copy-and-paste) and TightVNCServer.
4 - Editing vncserver's xstartup file.
5 - Setting-up SSH tunneling on our local machine using the gcloud command-line tool.
6 - Installing Gnome-Shell and Gnome-Panel
7 - Adding some missing elements to the desktop and enabling right-click using the Gnome Tweak Tool.

**COMMANDS**
$ sudo apt-get update
$ sudo apt-get upgrade
$ sudo apt-get install gnome-shell
$ sudo apt-get install ubuntu-gnome-desktop
$ sudo apt-get install autocutsel
$ sudo apt-get install tightvncserver
$ touch ~/.Xresources
$ sudo apt-get install gnome-core
$ sudo apt-get install gnome-panel
$ sudo apt-get install gnome-themes-standard
$ sudo apt-get install adwaita-icon-theme-full adwaita-icon-theme
$ gsettings get org.gnome.metacity theme
$ gsettings set org.gnome.metacity theme 'Adwaita'
$ vncserver -geometry 1024x640
$ vncserver -kill :1

**XSTARTUP FILE**
#!/bin/sh
autocutsel -fork
xrdb $HOME/.Xresources
xsetroot -solid grey
export XKL_XMODMAP_DISABLE=1
export XDG_CURRENT_DESKTOP="GNOME-Flashback:Unity"
export XDG_MENU_PREFIX="gnome-flashback-"
unset DBUS_SESSION_BUS_ADDRESS
gnome-session --session=gnome-flashback-metacity --disable-acceleration-check --debug &

**LOCAL SHELL COMMAND**
$ gcloud compute ssh \
YOUR INSTANCE NAME HERE \
--project YOUR PROJECT NAME HERE \
--zone YOUR TIMEZONE HERE \
--ssh-flag "-L 5901:localhost:5901"

**GNOME DESKTOP INSTANCE SHELL COMMAND**
$ sudo gnome-tweak-tool