Comment 21 for bug 692462

As I suspected this is wrong. It should be instead:
 WM_CLASS(STRING) = "chromium-browser", "mail.google.com__mail_u_0"

Chromium must be fixed, it's just a one-line patch to invert the parameters to gtk_window_setwmclass, we should fix this in ubuntu quickly if chromium won't do it.
Read more at: http://code.google.com/p/chromium/issues/detail?id=20587#c50