Google chrome is a great browser, which automatically keeps itself up to date. For some reasons, it keeps all older versions which eat up disk space. This becomes obvious when your hard drive storage is not *that* big (as on my Macbook Air with a 64 GB SSD).
I wondered why my free disk space constantly shrinks. On linux, baobab is a great tool to visualize the file sizes on you system. I googled for alternatives on mac and found a java program called jdiskreport, which does the job.
In my case, the google chrome app folder was about 2 gigs big, growing since about 1.5 years of usage. It turned out that over 90 percent of that usage was taken by old versions of chrome which aren't useful anymore.
Where are the versions located?
the standard path is
How to get rid of the older versions?
You can simply delete them.
cd /Applications/Google Chrome.app/Contents/Versions
into a terminal and use ls to see which versions are installed.
now you should delete all the versions but the actual version (with the highest number), e.g.
sudo rm -fr 21.0.1180.79
to delete the version 21.0.1180.79.
The command remove (rm) has to be used with sudo to gain administrative rights.
Another, even simpler possibility ist to just delete chrome from the /Application folder and download and reinstall chrome.