(Concept patch) Simplify WTF::HashTable::add() return value for size and performance

Source/core/inspector/DOMPatchSupport.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 226 matching lines @@
         oldMap[oldIndex].second = newIndex;
         newMap[newIndex].first = newList[newIndex].get();
         newMap[newIndex].second = oldIndex;
     }
 
     typedef HashMap<String, Vector<size_t> > DiffTable;
     DiffTable newTable;
     DiffTable oldTable;
 
     for (size_t i = 0; i < newList.size(); ++i) {
-        DiffTable::iterator it = newTable.add(newList[i]->m_sha1, Vector<size_t>()).iterator;
-        it->value.append(i);
+        newTable.add(newList[i]->m_sha1, Vector<size_t>()).iterator->value.append(i);
     }
 
     for (size_t i = 0; i < oldList.size(); ++i) {
-        DiffTable::iterator it = oldTable.add(oldList[i]->m_sha1, Vector<size_t>()).iterator;
-        it->value.append(i);
+        oldTable.add(oldList[i]->m_sha1, Vector<size_t>()).iterator->value.append(i);
     }
 
     for (DiffTable::iterator newIt = newTable.begin(); newIt != newTable.end(); ++newIt) {
         if (newIt->value.size() != 1)
             continue;
 
         DiffTable::iterator oldIt = oldTable.find(newIt->key);
         if (oldIt == oldTable.end() || oldIt->value.size() != 1)
             continue;
 
@@ skipping 244 matching lines @@
 void DOMPatchSupport::dumpMap(const ResultMap& map, const String& name)
 {
     fprintf(stderr, "\n\n");
     for (size_t i = 0; i < map.size(); ++i)
         fprintf(stderr, "%s[%lu]: %s (%p) - [%lu]\n", name.utf8().data(), i, map[i].first ? nodeName(map[i].first->m_node).utf8().data() : "", map[i].first, map[i].second);
 }
 #endif
 
 } // namespace WebCore