Chromium - Httqm's Docs

Every time I open Chromium, I get a pop-up asking :

Enter password to unlock your keyring

Let's make this clear, Chromium :

I have no such keyring
I'm not looking forward using one (not with you, at least)
I won't let you manage my logins and passwords
I just want to visit websites unlogged

Stop harassing me with this f*cking prompt every time !!!

The idea is to let Chromium use a basic (i.e. unencrypted) password store. This is done by passing it the --password-store=basic startup option.
The way you'll specify such options depends on how you're actually starting the application : from the "Start menu", a desktop launcher, ...
Editing "Start menu" options depends on your desktop environment; here's the information for XFCE.

This is a quick'n'dirty version of the XFCE procedure linked above. Understand what you type, use at your own risks.

As root :

edit /usr/share/applications/chromium.desktop
change
Exec=/usr/bin/chromium %U
into
Exec=/usr/bin/chromium %U --password-store=basic
forbid changes to this file :
chattr +i /usr/share/applications/chromium.desktop

as root :

configFile='/usr/share/applications/chromium.desktop'; sed -i 's|Exec=/usr/bin/chromium %U|Exec=/usr/bin/chromium %U --password-store=basic|' "$configFile" && chattr +i "$configFile"

Chromium - Another open source browser

Chromium : Enter password to unlock your keyring

Situation

Details

Solution