nsIAppShellService
nativeappsupport nsinativeappsupport getter for "native application support." read only.
... nativeappsupportorsplashscreen is an object that can be queryinterface'd to either an nsinativeappsupport or nsisplashscreen; this object will be used to implement hidesplashscreen.

nsIAppStartup
nativeappsupport nsinativeappsupport getter for "native application support." read only.
... void initialize( in nsisupports nativeappsupportorsplashscreen ); parameters nativeappsupportorsplashscreen is an object that can be qi'd to either an nsinativeappsupport or nsisplashscreen; this object will be used to implement hidesplashscreen.