IndexedDB: Make DOMException messages more useful.

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 140 matching lines @@
 short IDBFactory::cmp(ScriptExecutionContext* context, const ScriptValue& firstValue, const ScriptValue& secondValue, ExceptionState& es)
 {
     DOMRequestState requestState(context);
     RefPtr<IDBKey> first = scriptValueToIDBKey(&requestState, firstValue);
     RefPtr<IDBKey> second = scriptValueToIDBKey(&requestState, secondValue);
 
     ASSERT(first);
     ASSERT(second);
 
     if (!first->isValid() || !second->isValid()) {
-        es.throwDOMException(DataError);
+        es.throwDOMException(DataError, IDBDatabase::notValidKeyErrorMessage);
         return 0;
     }
 
     return static_cast<short>(first->compare(second.get()));
 }
 
 } // namespace WebCore