Specifically: nsDocShell::DisplayLoadError Most of these error messages have the brand name hard coded in, which isn't so great. So we should probably do something like nsDocShell::ConfirmRepost to look for a brandShortName in the brand bundle and format accordingly.

A first pass. There is an opportunity for pulling out some more stuff into a help method (checking for brandname, assigning) that could be reused so that other error types could be changed over with little effort. Also, it currently breaks if there isn't an override (or maybe because it's still trying to do the formatting). And I think this is leaking unless it's from something else I have applied. I'm willing to keep moving on this if this is a good start. Otherwise somebody with more familiarity here can take over.

After talking with Axel, he thinks it best to hold off for bug 545699 - the argument being that just substituting strings sucks, especially when brandShortName changes gender. Others disagree. The argument being that since it's brand specific, localizers could just leave their strings as is (still would need to change the lookup key) and this just becomes an opt-in for the languages that can handle substitution easily. So I'll do more work here (leave l20n blocking for now), and we can file a followup for whatever l20n specific things come up if need be.

My 2nd pass. This makes it so (many of) the other strings that have Firefox hard coded can use brand substitution. This is still not quite ideal since there are other strings here that have Firefox hard coded but are also substituting a URL so need additional processing (eg. fileNotFound, protocolNotFound, etc) I also made nsDocShell::ConfirmRepost use GetPromptAndStringBundles (because it was doing the same thing anyway). Maybe that should be done separately...