Ubuntu: Modify AWN to show Chrome's app dock icons more precisely.

When make a shortcut to Chrome application on AWN dock. the icon didnot change to their favicon or our customized icon.

    This is how to do that :-
i.e.:
chromium-browser --user-data-dir=~/.gmail --app=http://www.gmail.com --class=Gmail $*

Explanation
chromium-browser < Chrome executable >
--user-data-dir="< data directory for an app (linuz's) usually is $HOME/.config/google-chrome >"
--app="< URL of an app e.g.: https://docs.google.com/#home" >"
--class="< Name that make this shortcut unique e.g.: Docs $* >"

e.g.:
/usr/bin/chromium-browser --user-data-dir="/home/xample/.config/google-chrome/Default" --app="https://docs.google.com/#home" --class="Docs $*"