I received this GLSA about Chromium via feed. I recalled I could get notified by emerge, but I might be mistaken. Anyway, I used glsa-check to get a list of affected packages, it turned out there was one GLSA issued last year:

http://4.bp.blogspot.com/-EKeav_P5ytQ/Tz_5cc0XBAI/AAAAAAAADAQ/JMI5R7yqsrA/s800/2012-02-19--03:11:06.png

Its nice to have a command for updating package because of security issues, but the commands is little complicated to remember if you compare with revdep-rebuild1. I wrote this post with screenshot, so I could get the commands when next time I need them. :)

glsa-check -l
glsa-check -t all
glsa-check -p $(glsa-check -t all)
sudo glsa-check -f $(glsa-check -t all)
[1]I personally have no need to run it for some time, I used to do so by weekly if necessary, now only monthly without ever running it.