I am suspicious that that's not really sufficient password protection. What protection do you have from an attack that provides access to your machine's address space? (or chrome's address space)?
I'd like to see the source code before I use this. If that sounds paranoid, it's because if I'm using crypto, it's because I'm concerned about snoopers.
--- edit - source got posted. Thanks!
I'm guessing someone with that sort of threat model isn't using gmail for comms. (I guess even then, it could be useful to verify signatures (when gmail doesn't break the mail) without risking your private key)
This would also mean you don't have to reenter your password every time.