# Install x-related to compile x11vnc from source code.
sudo apt-get update 
sudo apt-get install -y libxtst-dev libssl-dev libjpeg-dev

# Grep source code.
wget http://x11vnc.sourceforge.net/dev/x11vnc-0.9.14-dev.tar.gz
gzip -dc x11vnc-0.9.14-dev.tar.gz | tar -xvf -
cd x11vnc-0.9.14/
./configure --prefix=/usr/local CFLAGS='-g -O2 -fno-stack-protector -Wall'

# Make and Make install.
make
make install

# Grep lighdm auth file.
ps wwwwaux | grep auth

# Run x11vnc.
/usr/local/bin/x11vnc -auth /var/run/lightdm/root/:0 -display :0 -xkb -forever -shared -rfbport 20000

# Use the chrome vnc client. Login Ubuntu and press ESC. Problems solved.

https://gist.github.com/mangoliou/407d6a39a60d128610c20c4143f39f0d

https://www.renyiwei.com/archives/1813.html

http://www.karlrunge.com/x11vnc/x11vnc_opts.html