Hold on to a profile lock. Once you release the last reference to this
 interface, the profile lock is released.
[scriptable, uuid(50e07b0a-f338-4da3-bcdb-f4bb0db94dbe)]
interface nsIProfileLock : nsISupports

Attributes

 The main profile directory.
readonly attribute nsILocalFile directory 
 A directory corresponding to the main profile directory that exists for
 the purpose of storing data on the local filesystem, including cache
 files or other data files that may not represent critical user data.
 (e.g., this directory may not be included as part of a backup scheme.)

 In some cases, this directory may just be the main profile directory.
readonly attribute nsILocalFile localDirectory

Methods

 Unlock the profile.
void unlock()