Chromium has more bugs than devs to fix them all. There have been heated debates on chromium-dev about what to do about old bugs. Some devs think they should stay open till they are fixed, but given Chromium's development pace that doesn't necessarily make sense. So they close them, assuming if the bug is still relevant it will be reopened.
One way they prioritize bugs (I believe) is by the number of times the bug has been starred.
I do not believe they have separate bug databases. They do have the ability to mark bugs private, which afaik is only used for security issues.
This is a slightly worse version of the behavior that prompted JWZ's first rant about bugtrackers in open source software (cf. http://www.jwz.org/doc/cadt.html ).
One way they prioritize bugs (I believe) is by the number of times the bug has been starred.
I do not believe they have separate bug databases. They do have the ability to mark bugs private, which afaik is only used for security issues.