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

Source/bindings/dart/custom/DartDOMStringMap.h

 // 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.
 
 #ifndef DartDOMStringMap_h
 #define DartDOMStringMap_h
 
 #include "bindings/dart/DartDOMWrapper.h"
 #include "core/dom/DOMStringMap.h"
 
 #include <dart_api.h>
 
 namespace WebCore {
 
 struct DartDOMStringMap {
     static const char* const dartImplementationClassName;
     static const char* const dartImplementationLibraryName;
+    static intptr_t kBindingCid;
     typedef DOMStringMap NativeType;
     const static bool isNode = false;
     const static bool isEventTarget = false;
     const static bool isActive = false;
 
     static PassRefPtr<NativeType> toNative(Dart_Handle handle, Dart_Handle& exception)
     {
         return DartDOMWrapper::unwrapDartWrapper<DartDOMStringMap>(handle, exception);
     }
 
     static Dart_Handle toDart(DOMStringMap* value)
     {
         return DartDOMWrapper::toDart<DartDOMStringMap>(value);
     }
 
     static Dart_Handle toDart(PassRefPtr< DOMStringMap > value)
     {
         return toDart(value.get());
     }
 
     static Dart_NativeFunction resolver(Dart_Handle name, int argumentCount);
 };
 
 }
 
 #endif // DartDOMStringMap_h