[bindings] Introduce ScriptValue.to<T> to convert to native values.

Source/modules/indexeddb/IDBFactory.cpp

 /*
  * Copyright (C) 2010 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:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 137 matching lines @@
         request->onError(DOMError::create(UnknownError, permissionDeniedErrorMessage));
         return request;
     }
 
     Platform::current()->idbFactory()->deleteDatabase(name, WebIDBCallbacksImpl::create(request).leakPtr(), createDatabaseIdentifierFromSecurityOrigin(scriptState->executionContext()->securityOrigin()));
     return request;
 }
 
 short IDBFactory::cmp(ScriptState* scriptState, const ScriptValue& firstValue, const ScriptValue& secondValue, ExceptionState& exceptionState)
 {
-    IDBKey* first = scriptValueToIDBKey(scriptState->isolate(), firstValue);
-    IDBKey* second = scriptValueToIDBKey(scriptState->isolate(), secondValue);
+    IDBKey* first = firstValue.to<IDBKey*>(exceptionState);
+    IDBKey* second = secondValue.to<IDBKey*>(exceptionState);
 
     ASSERT(first);
     ASSERT(second);
 
     if (!first->isValid() || !second->isValid()) {
         exceptionState.throwDOMException(DataError, IDBDatabase::notValidKeyErrorMessage);
         return 0;
     }
 
     return static_cast<short>(first->compare(second));
 }
 
 } // namespace blink