--- a/docshell/shistory/nsSHistory.cpp
+++ b/docshell/shistory/nsSHistory.cpp
@@ -583,17 +583,17 @@ nsSHistory::GetEntryAtIndex(int32_t aInd
         NOTIFY_LISTENERS(OnIndexChanged, (mIndex))
       }
     }
   }
   return rv;
 }
 
 /* Get the transaction at a given index */
-NS_IMETHODIMP
+nsresult
 nsSHistory::GetTransactionAtIndex(int32_t aIndex, nsISHTransaction** aResult)
 {
   nsresult rv;
   NS_ENSURE_ARG_POINTER(aResult);
 
   if (mLength <= 0 || aIndex < 0 || aIndex >= mLength) {
     return NS_ERROR_FAILURE;
   }
@@ -1698,17 +1698,17 @@ nsSHistory::LoadNextPossibleEntry(int32_
     return LoadEntry(aNewIndex - 1, aLoadType, aHistCmd);
   }
   if (aNewIndex > mIndex) {
     return LoadEntry(aNewIndex + 1, aLoadType, aHistCmd);
   }
   return NS_ERROR_FAILURE;
 }
 
-NS_IMETHODIMP
+nsresult
 nsSHistory::LoadEntry(int32_t aIndex, long aLoadType, uint32_t aHistCmd)
 {
   if (!mRootDocShell) {
     return NS_ERROR_FAILURE;
   }
 
   nsCOMPtr<nsIURI> nextURI;
   nsCOMPtr<nsISHEntry> prevEntry;

--- a/docshell/shistory/nsSHistory.h
+++ b/docshell/shistory/nsSHistory.h
@@ -78,25 +78,24 @@ public:
   // Otherwise, it comes straight from the pref.
   static uint32_t GetMaxTotalViewers() { return sHistoryMaxTotalViewers; }
 
 private:
   virtual ~nsSHistory();
   friend class nsSHEnumerator;
   friend class nsSHistoryObserver;
 
-  // Could become part of nsIWebNavigation
-  NS_IMETHOD GetTransactionAtIndex(int32_t aIndex, nsISHTransaction** aResult);
+  nsresult GetTransactionAtIndex(int32_t aIndex, nsISHTransaction** aResult);
   nsresult LoadDifferingEntries(nsISHEntry* aPrevEntry, nsISHEntry* aNextEntry,
                                 nsIDocShell* aRootDocShell, long aLoadType,
                                 bool& aDifferenceFound);
   nsresult InitiateLoad(nsISHEntry* aFrameEntry, nsIDocShell* aFrameDS,
                         long aLoadType);
 
-  NS_IMETHOD LoadEntry(int32_t aIndex, long aLoadType, uint32_t aHistCmd);
+  nsresult LoadEntry(int32_t aIndex, long aLoadType, uint32_t aHistCmd);
 
 #ifdef DEBUG
   nsresult PrintHistory();
 #endif
 
   // Evict content viewers in this window which don't lie in the "safe" range
   // around aIndex.
   void EvictOutOfRangeWindowContentViewers(int32_t aIndex);