Bug 392649 https add-on install from filepicker crashes [@ net_GetURLSpecFromFile]

r=biesi sr=biesi a=bz

netwerk/base/src/nsStandardURL.cpp

@@ -2497,7 +2497,7 @@ nsStandardURL::SetFile(nsIFile *file)
 {
     ENSURE_MUTABLE();
 
-    NS_PRECONDITION(file, "null pointer");
+    NS_ENSURE_ARG_POINTER(file);
 
     nsresult rv;
     nsCAutoString url;

netwerk/protocol/file/src/nsFileProtocolHandler.cpp

@@ -326,6 +326,7 @@ nsFileProtocolHandler::AllowPort(PRInt32 port, const char *scheme, PRBool *resul
 NS_IMETHODIMP
 nsFileProtocolHandler::NewFileURI(nsIFile *file, nsIURI **result)
 {
+    NS_ENSURE_ARG_POINTER(file);
     nsresult rv;
 
     nsCOMPtr<nsIFileURL> url = new nsStandardURL(PR_TRUE);