Add an interface for nested URIs (like jar:, view-source:, etc) to implement

and use it in various places.  Create null principals if asked for a codebase
principal for a codebase that doesn't have an inherent security context (eg
data: or javascript:).  Bug 334407, r=biesi,dveditz, sr=darin

netwerk/build/nsNetModule.cpp

@@ -226,6 +226,7 @@ NS_GENERIC_FACTORY_CONSTRUCTOR(nsGopherHandler)
 #ifdef NECKO_PROTOCOL_viewsource
 #include "nsViewSourceHandler.h"
 NS_GENERIC_FACTORY_CONSTRUCTOR(nsViewSourceHandler)
+NS_GENERIC_FACTORY_CONSTRUCTOR(nsViewSourceURI)
 #endif
 
 #ifdef NECKO_PROTOCOL_data
@@ -1133,6 +1134,11 @@ static const nsModuleComponentInfo gNetModuleInfo[] = {
       NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX "view-source",
       nsViewSourceHandlerConstructor
     },
+    { "The ViewSource URI", 
+      NS_VIEWSOURCEURI_CID,
+      nsnull,
+      nsViewSourceURIConstructor
+    },
 #endif
 
 #ifdef XP_WIN