diff --git a/gfx/thebes/gfxDWriteFontList.cpp b/gfx/thebes/gfxDWriteFontList.cpp
index 5c4cae5c78d5..31cdec52fe4a 100644
--- a/gfx/thebes/gfxDWriteFontList.cpp
+++ b/gfx/thebes/gfxDWriteFontList.cpp
@@ -1896,9 +1896,9 @@ private:
 
     RefPtr<IDWriteFactory>      mFactory;
 
-    nsCOMPtr<nsIFile>             mFontDir;
-    nsCOMPtr<nsISimpleEnumerator> mEntries;
-    nsCOMPtr<nsISupports>         mCurrent;
+    nsCOMPtr<nsIFile>                mFontDir;
+    nsCOMPtr<nsIDirectoryEnumerator> mEntries;
+    nsCOMPtr<nsISupports>            mCurrent;
 };
 
 BundledFontFileEnumerator::BundledFontFileEnumerator(IDWriteFactory *aFactory,