Improve modules' TypeError exception messages.

Source/modules/indexeddb/IDBObjectStore.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 378 matching lines @@
     }
     if (!m_transaction->isActive()) {
         exceptionState.throwDOMException(TransactionInactiveError, IDBDatabase::transactionInactiveErrorMessage);
         return 0;
     }
     if (!keyPath.isValid()) {
         exceptionState.throwDOMException(SyntaxError, "The keyPath argument contains an invalid key path.");
         return 0;
     }
     if (name.isNull()) {
-        exceptionState.throwUninformativeAndGenericTypeError();
+        exceptionState.throwTypeError("The name provided is null.");
         return 0;
     }
     if (containsIndex(name)) {
         exceptionState.throwDOMException(ConstraintError, "An index with the specified name already exists.");
         return 0;
     }
 
     if (keyPath.type() == IDBKeyPath::ArrayType && multiEntry) {
         exceptionState.throwDOMException(InvalidAccessError, "The keyPath argument was an array and the multiEntry option is true.");
         return 0;
@@ skipping 207 matching lines @@
     }
     return IDBIndexMetadata::InvalidId;
 }
 
 WebIDBDatabase* IDBObjectStore::backendDB() const
 {
     return m_transaction->backendDB();
 }
 
 } // namespace WebCore