Follow up to crash fix for bug 240397.

toolkit/components/places/src/nsNavHistoryAutoComplete.cpp

@@ -490,11 +490,12 @@ nsNavHistory::AutoCompleteFullHistorySearch(const nsAString& aSearchString,
                                AUTOCOMPLETE_MATCHES_SCHEME_PENALTY, &matches);
   }
 
+  // fill into result
+  if (matches.Length() > 0) {
     // sort according to priorities
     AutoCompleteResultComparator comparator(this);
     matches.Sort(comparator);
 
-  // fill into result
     rv = aResult->AppendMatch(matches[0].url, matches[0].title);
     NS_ENSURE_SUCCESS(rv, rv);
     for (i = 1; i < matches.Length(); i ++) {
@@ -505,6 +506,7 @@ nsNavHistory::AutoCompleteFullHistorySearch(const nsAString& aSearchString,
         NS_ENSURE_SUCCESS(rv, rv);
       }
     }
+  }
   return NS_OK;
 }