diff --git a/docshell/base/nsDefaultURIFixup.cpp b/docshell/base/nsDefaultURIFixup.cpp
index e73649759996..09a3e89f4188 100644
--- a/docshell/base/nsDefaultURIFixup.cpp
+++ b/docshell/base/nsDefaultURIFixup.cpp
@@ -1071,7 +1071,7 @@ nsDefaultURIFixup::KeywordURIFixup(const nsACString& aURIString,
 }
 
 bool
-nsDefaultURIFixup::IsDomainWhitelisted(const nsAutoCString aAsciiHost,
+nsDefaultURIFixup::IsDomainWhitelisted(const nsACString& aAsciiHost,
                                        const uint32_t aDotLoc)
 {
   if (sDNSFirstForSingleWords) {
@@ -1098,7 +1098,7 @@ nsDefaultURIFixup::IsDomainWhitelisted(const nsACString& aDomain,
                                        const uint32_t aDotLoc,
                                        bool* aResult)
 {
-  *aResult = IsDomainWhitelisted(nsAutoCString(aDomain), aDotLoc);
+  *aResult = IsDomainWhitelisted(aDomain, aDotLoc);
   return NS_OK;
 }
 
diff --git a/docshell/base/nsDefaultURIFixup.h b/docshell/base/nsDefaultURIFixup.h
index 4a37438e9394..9616281f8eaf 100644
--- a/docshell/base/nsDefaultURIFixup.h
+++ b/docshell/base/nsDefaultURIFixup.h
@@ -40,7 +40,7 @@ private:
   bool PossiblyHostPortUrl(const nsACString& aUrl);
   bool MakeAlternateURI(nsIURI* aURI);
   bool IsLikelyFTP(const nsCString& aHostSpec);
-  bool IsDomainWhitelisted(const nsAutoCString aAsciiHost,
+  bool IsDomainWhitelisted(const nsACString& aAsciiHost,
                            const uint32_t aDotLoc);
 };