diff --git a/content/base/src/nsDocumentEncoder.cpp b/content/base/src/nsDocumentEncoder.cpp
index 9c40e5f46f5..d47c52bb97a 100644
--- a/content/base/src/nsDocumentEncoder.cpp
+++ b/content/base/src/nsDocumentEncoder.cpp
@@ -1463,16 +1463,16 @@ nsHTMLCopyEncoder::GetPromotedPoint(Endpoint aWhere, nsIDOMNode *aNode, PRInt32
       {
         if (bResetPromotion)
         {
-          nsAutoString tag;
-          nsCOMPtr<nsIAtom> atom;
           nsCOMPtr<nsIContent> content = do_QueryInterface(parent);
           if (content)
           {
-            PRBool isBlock = PR_FALSE;
-            PRInt32 id;
+            nsCOMPtr<nsIAtom> atom;
             content->GetTag(getter_AddRefs(atom));
-            atom->ToString(tag);
-            parserService->HTMLStringTagToId(tag, &id);
+
+            PRInt32 id;
+            parserService->HTMLAtomTagToId(atom, &id);
+
+            PRBool isBlock = PR_FALSE;
             parserService->IsBlock(id, isBlock);
             if (isBlock)
             {
@@ -1552,16 +1552,16 @@ nsHTMLCopyEncoder::GetPromotedPoint(Endpoint aWhere, nsIDOMNode *aNode, PRInt32
       {
         if (bResetPromotion)
         {
-          nsAutoString tag;
-          nsCOMPtr<nsIAtom> atom;
           nsCOMPtr<nsIContent> content = do_QueryInterface(parent);
           if (content)
           {
-            PRBool isBlock = PR_FALSE;
-            PRInt32 id;
+            nsCOMPtr<nsIAtom> atom;
             content->GetTag(getter_AddRefs(atom));
-            atom->ToString(tag);
-            parserService->HTMLStringTagToId(tag, &id);
+
+            PRInt32 id;
+            parserService->HTMLAtomTagToId(atom, &id);
+
+            PRBool isBlock = PR_FALSE;
             parserService->IsBlock(id, isBlock);
             if (isBlock)
             {
diff --git a/content/base/src/nsPlainTextSerializer.cpp b/content/base/src/nsPlainTextSerializer.cpp
index f2851f16ead..5a2472b4f7e 100644
--- a/content/base/src/nsPlainTextSerializer.cpp
+++ b/content/base/src/nsPlainTextSerializer.cpp
@@ -1863,19 +1863,12 @@ nsPlainTextSerializer::GetIdForContent(nsIContent* aContent,
   mContent->GetTag(getter_AddRefs(tagname));
   if (!tagname) return NS_ERROR_FAILURE;
   
-  nsAutoString namestr;
-  tagname->ToString(namestr);
-  
   nsIParserService* parserService =
     nsContentUtils::GetParserServiceWeakRef();
   if (!parserService)
     return NS_ERROR_FAILURE;
 
-  nsresult rv;
-  rv = parserService->HTMLStringTagToId(namestr, aID);
-  if (NS_FAILED(rv)) return NS_ERROR_FAILURE;
-
-  return NS_OK;
+  return parserService->HTMLAtomTagToId(tagname, aID);
 }
 
 /**