Bug 767957 - Remove dead null-check for shistory in {push,replace}State. r=bz

docshell/base/nsDocShell.cpp

@@ -9859,17 +9859,6 @@ nsDocShell::AddState(nsIVariant *aData, const nsAString& aTitle,
 
     } // end of same-origin check
 
-    nsCOMPtr<nsISHistory> sessionHistory = mSessionHistory;
-    if (!sessionHistory) {
-        // Get the handle to SH from the root docshell
-        GetRootSessionHistory(getter_AddRefs(sessionHistory));
-    }
-    NS_ENSURE_TRUE(sessionHistory, NS_ERROR_FAILURE);
-
-    nsCOMPtr<nsISHistoryInternal> shInternal =
-        do_QueryInterface(sessionHistory, &rv);
-    NS_ENSURE_SUCCESS(rv, rv);
-
     // Step 3: Create a new entry in the session history. This will erase
     // all SHEntries after the new entry and make this entry the current
     // one.  This operation may modify mOSHE, which we need later, so we