diff --git a/mozilla/layout/build/nsLayoutCID.h b/mozilla/layout/build/nsLayoutCID.h
index 306445c5a93..743a5b7cc72 100644
--- a/mozilla/layout/build/nsLayoutCID.h
+++ b/mozilla/layout/build/nsLayoutCID.h
@@ -69,6 +69,10 @@
 #define NS_HTMLSTYLESHEET_CID \
 { 0x96882b70, 0x8a27, 0x11d2, { 0x8e, 0xaf, 0x0, 0x80, 0x5f, 0x29, 0xf3, 0x70 } }
 
+// {95F46161-D177-11d2-BF86-00105A1B0627}
+#define NS_HTML_CSS_STYLESHEET_CID \
+{ 0x95f46161, 0xd177, 0x11d2, { 0xbf, 0x86, 0x0, 0x10, 0x5a, 0x1b, 0x6, 0x27 } }
+
 // {96882B71-8A27-11d2-8EAF-00805F29F370}
 #define NS_TEXTNODE_CID \
 { 0x96882b71, 0x8a27, 0x11d2, { 0x8e, 0xaf, 0x0, 0x80, 0x5f, 0x29, 0xf3, 0x70 } }
diff --git a/mozilla/layout/build/nsLayoutFactory.cpp b/mozilla/layout/build/nsLayoutFactory.cpp
index 19b781e253b..8b9c906426d 100644
--- a/mozilla/layout/build/nsLayoutFactory.cpp
+++ b/mozilla/layout/build/nsLayoutFactory.cpp
@@ -33,6 +33,7 @@
 #include "nsIServiceManager.h"
 #include "nsICSSParser.h"
 #include "nsIHTMLStyleSheet.h"
+#include "nsIHTMLCSSStyleSheet.h"
 #include "nsIDOMRange.h"
 #include "nsIContentIterator.h"
 #include "nsINameSpaceManager.h"
@@ -46,6 +47,7 @@ static NS_DEFINE_IID(kCXMLDocumentCID, NS_XMLDOCUMENT_CID);
 static NS_DEFINE_IID(kCImageDocumentCID, NS_IMAGEDOCUMENT_CID);
 static NS_DEFINE_IID(kCCSSParserCID,     NS_CSSPARSER_CID);
 static NS_DEFINE_CID(kHTMLStyleSheetCID, NS_HTMLSTYLESHEET_CID);
+static NS_DEFINE_CID(kHTMLCSSStyleSheetCID, NS_HTML_CSS_STYLESHEET_CID);
 static NS_DEFINE_IID(kCHTMLImageElementCID, NS_HTMLIMAGEELEMENT_CID);
 static NS_DEFINE_IID(kCRangeListCID, NS_RANGELIST_CID);
 static NS_DEFINE_IID(kCRangeCID,     NS_RANGE_CID);
@@ -240,6 +242,12 @@ nsresult nsLayoutFactory::CreateInstance(nsISupports *aOuter,
       return res;
     refCounted = PR_TRUE;
   }
+  else if (mClassID.Equals(kHTMLCSSStyleSheetCID)) {
+    // XXX ibid
+    if (NS_FAILED(res = NS_NewHTMLCSSStyleSheet((nsIHTMLCSSStyleSheet**)&inst)))
+      return res;
+    refCounted = PR_TRUE;
+  }
   else if (mClassID.Equals(kTextNodeCID)) {
     // XXX ibid
     if (NS_FAILED(res = NS_NewTextNode((nsIContent**) &inst)))