A segmentation fault will occur, for example, if a program attempts to access memory that does not belong to it; then the kernel brings a hammer down. This is the result of a programming error.
It should absolutely unequivocally not be possible for you to force an end-user tool to do this, regardless of how you have used it. So that would be a bonefide bug, and you should report it.
The normal process of reporting a bug on linux begins "downstream", that is, with the last people responsible for the software before you got it (they then may report the bug "upstream", that is, closer to the people who actually wrote the code that produced the software). In this case that's important, since it's unlikely this is something that is happening for every user of chromium on linux -- even if it is because of a bug in the original source, it's probably important to the diagnosis that the context that caused it to surface to be isolated.
So you want to report that to raspbian, since they at least packaged (and probably compiled) the software as a last step before you the user used it.
Create an account, maybe have a look at a couple of bug reports (you'll probably end up doing that when you check to see if this has been reported already) to get the whycomes and wherefores of that, then just explain what you did here.