IndexedDB: Rely on bindings for enum validation

Source/modules/indexeddb/IDBTransaction.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 281 matching lines @@
 }
 
 bool IDBTransaction::hasPendingActivity() const
 {
     // FIXME: In an ideal world, we should return true as long as anyone has a or can
     //        get a handle to us or any child request object and any of those have
     //        event listeners. This is  in order to handle user generated events properly.
     return m_hasPendingActivity && !m_contextStopped;
 }
 
-WebIDBTransactionMode IDBTransaction::stringToMode(const String& modeString, ExceptionState& exceptionState)
+WebIDBTransactionMode IDBTransaction::stringToMode(const String& modeString)
 {
     if (modeString == IndexedDBNames::readonly)
         return WebIDBTransactionModeReadOnly;
     if (modeString == IndexedDBNames::readwrite)
         return WebIDBTransactionModeReadWrite;
-
-    exceptionState.throwTypeError("The mode provided ('" + modeString + "') is not one of 'readonly' or 'readwrite'.");
+    if (modeString == IndexedDBNames::versionchange)
+        return WebIDBTransactionModeVersionChange;
+    ASSERT_NOT_REACHED();
     return WebIDBTransactionModeReadOnly;
 }
 
 const String& IDBTransaction::mode() const
 {
     switch (m_mode) {
     case WebIDBTransactionModeReadOnly:
         return IndexedDBNames::readonly;
 
     case WebIDBTransactionModeReadWrite:
@@ skipping 87 matching lines @@
     event->setTarget(this);
     eventQueue->enqueueEvent(event);
 }
 
 WebIDBDatabase* IDBTransaction::backendDB() const
 {
     return m_database->backend();
 }
 
 } // namespace blink