(Note: This is just out of curiosity, hope this doesn't sound stupid or anything.) As I'm sure most of you know, every time Google Chrome is "shut down incorrectly" (eg. cutting the computer's power supply), it will display a yellow bar at the top the very next time it is opened, saying that it wasn't shut down correctly and offering to restore the pages that were last opened. How does it do that? More specifically, how does it detect that it wasn't shut down correctly? Thanks.