Keep a persistent handle for the bindings classes to avoid repeated lookups that involve performing…

Source/bindings/dart/custom/DartDOMStringMapCustom.cpp

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "config.h"
 #include "DartDOMStringMap.h"
 
 namespace WebCore {
 
 namespace DartDOMStringMapInternal {
@@ skipping 133 matching lines @@
     if (argumentCount == 2 && name == "DOMStringMap_remove_Callback")
         return DartDOMStringMapInternal::removeCallback;
     if (argumentCount == 1 && name == "DOMStringMap_getKeys_Callback")
         return DartDOMStringMapInternal::getKeysCallback;
 
     return 0;
 }
 
 const char* const DartDOMStringMap::dartImplementationClassName = "_DOMStringMap";
 const char* const DartDOMStringMap::dartImplementationLibraryName = "dart:html";
+const int DartDOMStringMap::dartClassId = DOMStringMapClassId;
 }